Celtics' Isaiah Thomas is a fourth-quarter killer, but which team is he killing?

[cousytoheinsohn]

These sorts of analysis have to be very careful.   The sample sizes involved cutting down a half season into just the 4th period means you are cutting a very small sample -- one that is normally considered way too small for statistical significance when doing plus/minus analysis -- into an even tinier one.

I would also caution that with plus-minus data individual and two-man analysis is often extremely misleading.  Collinearity effects can be dramatic, especially when some players play a ton of minutes together while others hardly ever play together.   A good example of this was last year when some 'analysts' decided to look at 2-man data that seemed to show that everybody played so much better without David Lee on the floor.  What their analysis didn't show was that the minutes people played without David Lee included large shares of time WITH Isaiah on the floor last year whereas David Lee himself played most of his minutes WITHOUT Isaiah on the floor.   

That presented a false result that it was Lee who was dragging the plus/minus of others down when in truth it was absence of time with IT.

Many fans here were surprised when Lee joined Dallas for the rest of last year and San Antonio this year and has posted very, very good numbers in each stint -- including excellent plus/minus numbers!   But folks who looked past the simplistic 2-man analysis were not surprised.

When using plus/minus data, it is much better to look at actual 5-man units.   These let you get a better picture of the actual configurations that are working and are not working.

One picture that materializes is that the three-guard problem is a real one - but especially when it involves using only one true big.

For example, the Isaiah+Avery+Marcus+Jae+Al 5-man unit has a truly horrid 127 defensive rating.

Every one of those players also has plenty of minutes on _other_ 5-man units that have fantastic defensive ratings.   For example, just swap Marcus for Jonas and you get a unit with a fantastic 97 DRtg!!!

Alternatively, however, if you instead swap out Crowder and put in Olynyk, (so you have a lineup of IT+AB+MS+AH+KO), that _also_ drops the DRtg significantly, down to 103.8, which is still excellent.

Neither of those swaps mean that Marcus or Jae are bad defenders.  Or that Jonas or Kelly are elite defenders capable of shaving dozens of points off the DRtg.

The p----poor rating of the first 3-guard unit up above doesn't mean _any_ of those 5 players are bad defensive players.   It means that it was a horrible defensive _unit_.

The alternative units with either Jonas or Kelly are far superior defensive units because they are better utilizations of the players involved.

Marcus at the 3 and/or Jae at the 4 are things that you can get away with situationally, but overall, they just aren't good defensive alignments.

We have 8 different 5-man units with at least 50 minutes on the floor that include Thomas.  Only two of those units -- the one noted above plus another made up of IT+MS+JC+AH+KO -- have 'bad' DRtgs (both are above 120).   

The other 5 most-used lineups with Thomas all are at or better than the team's overall 109.8 rating and go as low as the stifling 97 rating of the lineup with JJ mentioned above.

Some other things that come out of the analysis of 5-man data is that the vast majority of our 'better' 5-man units (both defensively and overall net rating) include at least 2 of our three best bigs (Al, Kelly & Amir) and the few good ones that don't include two from that set tend to include Al & Jonas.   

We have very few 5-man units with only one big that aren't in the negative, whereas almost all of our 5-man units with two true bigs are in the positive.

To me, all this suggests strongly this isn't an individual player issue.   This is a configuration & utilization issue.

Great points all around and particularly as regards David Lee. I always felt he was somebody, the oft-pined for true big with proven skills, in fact, who could have helped immensely if only someone could have figured out how to use him effectively. He was in the house and on a really cheap deal. It's easy to imagine how he would be helping this year based on his current level of play. That one's on Brad, in my opinion.

[Ilikesports17]

I think we just need a better defensive center to help anchor the defense. This would also raise the question of if IT is so bad for us why do we have the 5th best record in the conference and why were we abysmal when he was injured?

abysmal?

We were 1-3 with losses to Toronto at OKC and at the Spurs.
We also destroyed Orlando.

also, you meant NBA, not conference.

IT isnt bad for us, because his lights out offense more than makes up for his putrid defense but it is a legitimate concern that if you can slow him down on offense, his defense makes it really hard to win games down the stretch.

[Ogaju]

there are three kinds of lies...

Lies, White lies, and STATISTICS.

I know what I see with my eyes.... IT is a giant in the fourth quarter.

Without IT Celtics will still have their rebounding woes, but without the scoring to make up for it.

[GreenEnvy]

I refuse to believe one player can be surrounded by four great defensive players and the team instantly becomes terrible.

IT gets caught sometimes and will never be mistaken for an excellent defender, but he's not the sole reason for the defensive lapses.

I'm not gonna get all crazy into the numbers and lineups and such, but his DRtg was 107 last season. For reference, CP3, considered one of the best defenders at PG, has a 104 DRtg this season. That's a top 20 overall rating and 2nd far PG.

So what changed in since last year? Was the Celtics D hiding Isaiah? Perhaps, as it was his career best. But why are they so much worse this season? I think it's a collective effort, and Isaiah is not failing in the defensive end due to lack of effort. Bradley hasn't been as good as last year, Olynyk hasn't, Amir hasn't, and neither has Isaiah. The team can be better and should be. I expected them to be a top defensive team with the addition of Horford and at times they look like that team.

Overall, the only thing that matters is the record. They are winning games. I've heard December 20 being the start of his unbelievable run. Well, the team is 15-6 in those games, which by my math is a 59-win pace. If this guy is leading us to nearly 60 wins, I wouldn't spend so much time breaking down his defense or him "forcing" his offense, I'd sit back and enjoy hm for what he is: arguably the most exciting player in the league and without question an MVP candidate.

[CelticPride2016]

Great points all around and particularly as regards David Lee. I always felt he was somebody, the oft-pined for true big with proven skills, in fact, who could have helped immensely if only someone could have figured out how to use him effectively. He was in the house and on a really cheap deal. It's easy to imagine how he would be helping this year based on his current level of play. That one's on Brad, in my opinion.

The problem with that:

"David Lee Admits He Was Out Of Shape During Stint With Boston Celtics"
http://nesn.com/2016/03/david-lee-admits-he-was-out-of-shape-during-stint-with-boston-celtics/

It's called betrayal. David Lee stabbed us in the back. He used us. Sully also betrayed us. He looks mighty thin lately for Toronto, but we weren't good enough for him to get in shape for us who gave him every opportunity to succeed.

David Lee. He's getting old and was never known for defense. Humphries was the better of the two, imho, maybe Bass, for ex-Celtic bigs.

David Lee was a bad Danny move. Wallace was good for the atmosphere and every once in a while he could still stir a game up with his defense. It's like Danny has a blind spot. The new player doesn't need to be Noel or a young Gortat, not even necessarily a starter. But Danny needs to find that player who fits into the missing role. We all see the team's vulnerabilities. Amir, Al and Kelly do what they can as centers, but find a real center, and our team could go on a serious tear.

Sanders.

Maybe it will be the Orlando center. If we are waiting for Godot or Zizic, then we must pray to the basketball gods for this year that our best bigs can reach deep down inside and get it done. It's possible. I remember Humphries, Bass, Zeller, Sully and Olynyk. I remember Brandan Wright. Amir Johnson, Al Horford and the older Olynyk are a million times better than the bigs were when Stevens first got here. We do need rebounds. We are missing a center. How are we not missing a center? Having that player could further help to evaluate Isaiah Thomas and the article topic.

We can win with Isaiah. I agree. Build the team around him. He's a superstar. He is the NBA's best player on offense based on the eye test. We watch every game. He at least equals any other NBA player for offense. He proved it this year. If we score 120 points, that means the defense can give up 119. I'll take those odds. He does give us the chance to win games.

Rollie described Isaiah on another thread. He is a maestro, Mozart, Einstein and a lot of other guys.

[rocknrollforyoursoul]

Makes you pretty hesitant to add someone like Melo, huh?

It's not all IT's fault. He's terrible defensively due to his size, but playing Horford at the 4 also hurts us significantly due to his inability to guard out on the perimeter with stretch 4's, along with being smaller throughout the rest of the lineup.

It's no coincidence that we've played better with both JJ and Brown in the lineup to give us much more overall size. But in addition to more size, it gives our defenders the ability to actually play their natural positions defensively. Masslive posted last night just how dominant the trio of IT, Crowder, and JJ has been the last three years due to Crowder's and JJ's ability to stretch the floor while also defend at a high level:

One reason, Stevens said, is how well Jerebko plays alongside Isaiah Thomas.

"(Jerebko is) a guy that can space the floor," Stevens said before topping the Pistons, 113-109. "He's a guy that, when you have paint attacks, when you have more threats, obviously, he can be at his best, whether it's shooting or driving against the closeouts. "

During Jerebko's two-plus seasons with the Celtics, the team has dominated opponents when he shares the court with Thomas and Jae Crowder. The reasons seem simple; Crowder and Jerebko can both space the floor for their high-scoring teammate while covering, with length and mobility, for some of Thomas' defensive shortcomings. Over 185 minutes this season, that trio currently holds a +19.8 net rating, according to NBA.com. That's a tiny sample size, but the trend held last year (+15.9) and the season before that (+28.3). Ever since they all played on the bench -- which sounds weird now -- the Celtics have been killers with Thomas, Crowder and Jerebko on the court.

Now those guys are all starting -- and still finding similar results. Since Jerebko entered the first unit, the trio has racked up a +30.8 net rating over 78 minutes together, according to NBA.com. The Celtics always score with Thomas on the court, but have also defended at elite levels when he's surrounded by Jerebko and Crowder. During minutes with those three players, the Celtics have allowed 99.6 points per 100 possessions -- a defensive rating that would lead the NBA among all teams. If that number holds steady, it would be a huge deal for a club that has failed too frequently to make up for Thomas' defensive limitations.

That's crazy good and efficient.

It shows you the type of players that we need to be surrounding IT with - specifically "3 and D" type stretch 4's that give IT space offensively while also covering for his defensive weaknesses. Millsap and Ibaka come to mind as best fits for this mold, but Noel would also certainly work with his defensive abilities on the perimeter. He'd also provide an excellent roll man and lob partner for IT offensively.

Didn't know this, and I'm glad to hear that the team has hit upon a combination that really works on both sides of the ball. Hopefully Brad sticks with it. TP for the find.

[RockinRyA]

Isaiah was a minus 10 last night.
Crowder was a plus 7 and Smart was a plus 11.
But Isaiah has the guts and ability to make the big shots down the stretch. A lot of players on this team are afraid to take shots when the pressure is on.
I don't know the answer, but I like the idea of Fultz as our future point guard.

Yeah I agree. Thing about +/- stat is that while it can give you a lot of info about how a player impacts a game, its not foolproof. Not all minutes are equal. We sit down Thomas in the last 2 minutes and Im certain Crowder and Smart's +7 and +11 respectively will come down and we lose.

[Bobshot]

I watched some of the Detroit game replay today on NBA TV. The Celtics led by 11 early in the 4Q before IT took over. They won by 4 after he scored a barrel of points.

One thing I noticed about IT is he took a lot of 3s without waiting for anybody to get up the court with him. He pushed the ball up, stopped at the 3P line and shot the ball. Much of the time, he missed. No 2nd shot, since there were no Celtics near the basket for the OR. He also drove, recklessly at times, to the basket, missing layups and hitting some. Nobody else touched the ball.

The Celtics game is traditionally pass for the best shot--the game Pop copied for his Spurs successfully.

The Celtics clearly could benefit from another offensive player. A guy who can take the offensive pressure off IT. Nobody on the team seems to be able to do it. IT is the perfect fantasy player right now, but I'm not sure he's the perfect team player.

[saltlover]

I watched some of the Detroit game replay today on NBA TV. The Celtics led by 11 early in the 4Q before IT took over. They won by 4 after he scored a barrel of points.

One thing I noticed about IT is he took a lot of 3s without waiting for anybody to get up the court with him. He pushed the ball up, stopped at the 3P line and shot the ball. Much of the time, he missed. No 2nd shot, since there were no Celtics near the basket for the OR. He also drove, recklessly at times, to the basket, missing layups and hitting some. Nobody else touched the ball.

The Celtics game is traditionally pass for the best shot--the game Pop copied for his Spurs successfully.

The Celtics clearly could benefit from another offensive player. A guy who can take the offensive pressure off IT. Nobody on the team seems to be able to do it. IT is the perfect fantasy player right now, but I'm not sure he's the perfect team player.

IT went 3-6 from 3 in the 4th.  Based on the play-by-play, his three misses occurred 8 seconds into the shot clock, 17 seconds on the shot clock, and 15 seconds on the shot clock.  So what you're talking about happened at most once.  His makes occurred 13, 15, and 18 seconds into the shot clock.

Respectfully, I think you carried a bit of pre-judgment into your reviewing and saw something that didn't actually happen.

[Somebody]

This is more emphasized here in Euro basketball and I watch it with maybe other eyes than you in America in terms of two-sided game and showtime. His defense in the fourth quarters is as extreme as his offense. Nothing to everything, that's why I tell you that he would be benched by many Euro coaches.

What I have been thinking for some heroic games by the tiny guy is that he had to extinguish the fires he had been creating.

Don't misinterpret me. I enjoy a lot watching him being the best at the end of games attacking the rim and raining threes, and Thomas is the face of this franchise... but this article shows in numbers a reality. Is he really a max guy to be the first option in a championship team or should we try to deal him at his peak market value? That is the biggest question next summer.

Um I don't mean to be rude but I think that's why euros haven't won against usa basketball for quite a long time lol

[mmmmm]

I think we just need a better defensive center to help anchor the defense. This would also raise the question of if IT is so bad for us why do we have the 5th best record in the conference and why were we abysmal when he was injured?

I agree with these points celticsclay.

But to keep it fair to the article, Moore had anticipated them. First, Moore is not saying IT is bad for us in the absolute sense.

First, it's never one thing when the metrics are this messy. It's not like every single bucket scored is because Thomas is unable or unwilling to defend, and that's important in determining where to go from here. Here's what this data doesn't tell us:

It doesn't tell us that Isaiah Thomas is a bad NBA player who should be benched.

It doesn't tell us that the Celtics should bench Isaiah Thomas in the fourth.

It doesn't tell us that Thomas is the reason they are bad defensively.

And second, he makes it clear this is about the postseason

The Celtics are undefeated this season when leading going into the 4th quarter, and are 30-18 overall. They're winning anyway. There's a philosophy that as long as the Celtics are winning games, it's fine. They have the 2nd best record in the East, and a win over the Raptors Wednesday would give them a full two-game lead for 2nd. Does any of this matter?

Yes. It does. This isn't about whether the Celtics can beat the Pistons or Kings or Dallas in January. It's whether their defense will be good enough to hold off teams in the playoffs. Boston's 8-12 record vs. teams .500 or better is telling, as is their 1-8 record vs. the Warriors, Spurs, Rockets, Cavs, and Raptors. Boston can hold off teams with their offense in the regular season. They have to find a better formula for the postseason.

My problem with the analysis is that it doesn't really tell us much at all -- yet that doesn't stop Moore from putting it out there as if it does.  The disclaimers seem rather disingenuous.

The data he is using is insufficient to use for individual and 2-man on/off analysis.  It's bad statistics. 

[mmmmm]

Isaiah was a minus 10 last night.
Crowder was a plus 7 and Smart was a plus 11.
But Isaiah has the guts and ability to make the big shots down the stretch. A lot of players on this team are afraid to take shots when the pressure is on.
I don't know the answer, but I like the idea of Fultz as our future point guard.

Yeah I agree. Thing about +/- stat is that while it can give you a lot of info about how a player impacts a game, its not foolproof. Not all minutes are equal. We sit down Thomas in the last 2 minutes and Im certain Crowder and Smart's +7 and +11 respectively will come down and we lose.

Who was on the floor in this game a lot while IT was on the floor?

Andre Drummond, that's who.   Did everybody forget about him?   It just so happens that AD and IT were on the floor for almost the exact same minutes of this game.  IT was -10 mainly because AD was +12.

For IT to be "-10" in the game, that means points were scored by Detroit, right?  Well HOW were they scoring them?

They were scoring them with a ton of second-chance points based primarily on Drummond's rebounding dominance.   Detroit's three best big men, Drummond (28), Morris (13) and Harris (15) combined to score 56 points -- almost all of that in the paint (Morris made one 3PT shot).

Was all that dominance near the post Isaiah's fault?  Is he supposed to be defending the bigs now?

Five of the points that CAN be charged directly to Isaiah came on the two fouls on the KCP 3PT shot attempts that gave the latter 6 FT attempts (KCP made 5 of them).

But otherwise, the Pistons made hardly any of their shots from outside and their two starting guards shot horribly.  KCP shot 5 of 16, getting 5 of his 18 points from the two aforementioned plays and Jackson shot 4 of 12 and was in deep foul trouble all game.

[Ilikesports17]

Isaiah was a minus 10 last night.
Crowder was a plus 7 and Smart was a plus 11.
But Isaiah has the guts and ability to make the big shots down the stretch. A lot of players on this team are afraid to take shots when the pressure is on.
I don't know the answer, but I like the idea of Fultz as our future point guard.

Yeah I agree. Thing about +/- stat is that while it can give you a lot of info about how a player impacts a game, its not foolproof. Not all minutes are equal. We sit down Thomas in the last 2 minutes and Im certain Crowder and Smart's +7 and +11 respectively will come down and we lose.

Who was on the floor in this game a lot while IT was on the floor?

Andre Drummond, that's who.   Did everybody forget about him?   It just so happens that AD and IT were on the floor for almost the exact same minutes of this game.  IT was -10 mainly because AD was +12.

For IT to be "-10" in the game, that means points were scored by Detroit, right?  Well HOW were they scoring them?

They were scoring them with a ton of second-chance points based primarily on Drummond's rebounding dominance.   Detroit's three best big men, Drummond (28), Morris (13) and Harris (15) combined to score 56 points -- almost all of that in the paint (Morris made one 3PT shot).

Was all that dominance near the post Isaiah's fault?  Is he supposed to be defending the bigs now?

Five of the points that CAN be charged directly to Isaiah came on the two fouls on the KCP 3PT shot attempts that gave the latter 6 FT attempts (KCP made 5 of them).

But otherwise, the Pistons made hardly any of their shots from outside and their two starting guards shot horribly.  KCP shot 5 of 16, getting 5 of his 18 points from the two aforementioned plays and Jackson shot 4 of 12 and was in deep foul trouble all game.

Down the stretch Detroit absolutely feasted on Thomas. Thomas was absolutely helpless against him. Thing is, with about 5 minutes left Isaiah became unstoppable and the defense shortcomings became irrelevant.

[wiley]

read the article but not the thread.  Just want to say I'm a huge fan of defense, but am not worried in this case.  What we're missing is rim protection (make it less of a sure thing after getting by Thomas).
There have been so many great offensive talents who are pretty poor on defense.  When they have a defensive, intimidating big man backing them up articles like this one don't get written. 

[mmmmm]

Isaiah was a minus 10 last night.
Crowder was a plus 7 and Smart was a plus 11.
But Isaiah has the guts and ability to make the big shots down the stretch. A lot of players on this team are afraid to take shots when the pressure is on.
I don't know the answer, but I like the idea of Fultz as our future point guard.

Yeah I agree. Thing about +/- stat is that while it can give you a lot of info about how a player impacts a game, its not foolproof. Not all minutes are equal. We sit down Thomas in the last 2 minutes and Im certain Crowder and Smart's +7 and +11 respectively will come down and we lose.

Who was on the floor in this game a lot while IT was on the floor?

Andre Drummond, that's who.   Did everybody forget about him?   It just so happens that AD and IT were on the floor for almost the exact same minutes of this game.  IT was -10 mainly because AD was +12.

For IT to be "-10" in the game, that means points were scored by Detroit, right?  Well HOW were they scoring them?

They were scoring them with a ton of second-chance points based primarily on Drummond's rebounding dominance.   Detroit's three best big men, Drummond (28), Morris (13) and Harris (15) combined to score 56 points -- almost all of that in the paint (Morris made one 3PT shot).

Was all that dominance near the post Isaiah's fault?  Is he supposed to be defending the bigs now?

Five of the points that CAN be charged directly to Isaiah came on the two fouls on the KCP 3PT shot attempts that gave the latter 6 FT attempts (KCP made 5 of them).

But otherwise, the Pistons made hardly any of their shots from outside and their two starting guards shot horribly.  KCP shot 5 of 16, getting 5 of his 18 points from the two aforementioned plays and Jackson shot 4 of 12 and was in deep foul trouble all game.

Down the stretch Detroit absolutely feasted on Thomas. Thomas was absolutely helpless against him. Thing is, with about 5 minutes left Isaiah became unstoppable and the defense shortcomings became irrelevant.

What does that mean?  WHO "feasted on Thomas"?  Which player and how?

Per NBA/SportsVU player tracking, in the 4th period Thomas defended 3 DFGA, giving up 2 makes and he also got called for the two fouls I mentioned.  That's it.  That amounts to 9 points, over half of that came on the two fouls, one of which Stevens was howling at the refs over.

In the 4th period, Detroit's big men, Drummond, Morris, Harris and Leuer combined to score 22 points.   Which of those points were Isaiah's fault?