Bunch of ingrates 
That aside, Avery is a better player than Jaylen in almost EVERYTHING. We start the better player, plain and simple.
The best way to screw up this team's chemistry and send us back down a sh!tty path is what you guys are advocating.
Anybody remember Ray Allen/Bradley/Rondo/Doc fiasco? I could even stomach that one because Ray was injury prone and at the tale end of his career while the young Bradley was starting to come into his own but it messed up the team's chemistry which eventually led to Ray signing with the Lebron.
Jaylen is a f'ing rookie for godsakes...a rookie with many flaws still, starting in place of someone clearly better and someone with the longest tenure here. ****H.
That's not true . Brown as a rookie is already stronger, longer, healthier, better slasher, has more upside and more versatile defensively
Stronger? By what measure?
Longer? True
Healthier? He hasn't log as many minutes so I wouldn't say so
Better Slasher? LOL...ummm...NO
Has more upside? We'll see in couple years or so
More versatile defensively? NO
How about we talk things that are tangible and more important to this team such as offense, defense, rebounding, 3 pt percentage, perimeter defense, FT shooting percentage, experience, playoffs experience,...you know, those things Bradley is CLEARLY better at than Jaylen?
Stronger? Yes, he has 40-50lbs on him LOL
Longer? Yes
Healthier? So far, yes
Better slasher? Arguable but I would say yes. Avery mainly drives off of cuts and Jaylen can get to the rim seemingly at will and already is a better finisher
Higher upside? Yes
More versitile defensively? Yes
Seven game win streak? Yes
Bench is inconsistent? Yes
Brown plays better with starters? Yes
Smart and Bradley coming off the bench? Yikes
What else needs to be said
So much fail in this post I don't know where to begin. And the fact that you completely ignore the last part of my post says a lot. You didn't put up anything worth arguing so I won't even bother. Seven game win streak...smh #palmface
You were wrong on almost every single question you answered. And I'm not saying that brown should play more minutes than Bradley. Bradley should get he same amount of minutes coming off the bench and brown should get 10-15 minutes starting. Bradley is no doubt the better player, but when you consider the several factors like our young inconsistent bench, the advance stats that show that Avery and Isaiah aren't a good pairing defensivly, Avery has played his best basketball coming off the bench, Jaylen is playing A LOT better starting, playing better defense and consistently scoring double figures, and Jaylens superstar potential, you have to consider it
To be fair everyone is a bad defensive pairing next to IT.
Here are the 9 5-man units that the Celtics have played at least 50 minutes this year, sorted by defensive rating (points surrendered per 100 possessions):
Unit min ORtg DRtg NetRtg
TR+MS+JB+JJ+KO 59.2 100.0 94.0 +6.0
IT+AB+JC+JJ+AH 50.0 114.1 97.1 +17.0
IT+AB+MS+AH+KO 74.9 99.4 103.8 -4.5
IT+MS+JC+AH+AJ 118.1 119.6 107.2 +12.4
IT+AB+JC+AH+KO 59.2 127.6 108.3 +19.4
IT+AB+JC+AH+AJ 251.4 115.6 109.8 +5.9
MS+AB+JC+AH+AJ 63.3 120.5 111.6 +8.9
IT+MS+JC+AH+KO 71.8 120.7 120.8 -0.1
IT+AB+MS+JC+AH 63.9 116.3 127.1 -10.8
The team's overall defensive rating is about 109.2.
Thomas is on 7 of those 5-man units. Five of those seven range from team average to really, really excellent. This suggests that, no, not everyone is bad defensively pairing next to IT.
It is useful to look at the worst lineup (both by DRtg AND Net) and compare it to the second best lineup (also in both categories). The difference is simply swapping in Jerebko for Marcus. That simple change, which has nothing to do with Isaiah, transforms it from a cluster-mess to a really excellent lineup on both ends of the floor.
The difference between those two also isn't because Marcus is a crap defender and Jerebko is a super-elite one, either. The difference is the worst lineup has both Marcus and Jae playing 'small' and out of position whereas the swap transforms it to a conventional lineup, with everyone playing their normal position.
For the purposes of this particular thread, it is probably also important to note the top defensive unit (which is the 5th best NetRtg unit). That's our 'pure bench' unit (which has played primarily against opposing benches). This one shows that Jaylen Brown actually has played pretty well with the bench. The offense hasn't been super great with that unit, but a lot of that unit's minutes were from earlier in the year. Several of those guys are scoring the ball a lot better now than earlier in the year.
By pair, I mean two. Both AB and Brown have a negative rating starting next to IT.
Those numbers are all way wonkie anyway in comparison to what NBA.com has. The minute totals appear to be accurate but not the ratings. 50 and 100 minute samples are next to worthless.
The numbers are all from basketball-reference.com. http://bkref.com/tiny/to8l7
The samples are too small to make projections, but they are records of what has happened.
Basketball reference is just not accurate on a lot of stuff. Take the C's defensive rating for instance, the actual rating is 106.1 whereas BBRef shows 109.2. All those lineups are off, some of them by a lot. That 5 man unit data doesn't tell you anything definitive, just watch them and they will change dramatically from week to week as the the sample sizes are ridiculously small. 2 man pairings are not any less informative then 5 man units, sample size and context do matter and must be considered with both.
The bbref 5-man lineup data is based on raw point totals divided by possession counts. For example, the IT+AB+MS+JC+AH lineup has played 140 defensive possessions and surrendered 178 points, which results in it's 127.1 points per 100 possessions defensive rating.
I would not be surprised if the bb-ref numbers are off here or there. Different sites disagree sometimes. For example, nbawowy.com says that that lineup has played only 136 defensive possessions, surrendering 177 points, which results in a 130.1 rating. Which still sucks.
Over time, those disagreements will become small and not really that important. By any site, the same 5-man lineups tend to result in numbers that are close enough to the ones I presented that they support the same basic relative performance between these units.
I do not disagree that sample sizes at this point in the season are small. But as I stated earlier, I am not predicting anything here. I'm simply pointing out how the lineups have performed.
I disagree strongly that 2-man data has remotely close to the same analytical value as the 5-man data. You specifically assert that "context do matter", yet when you collapse below the 5-man data you have erased a ton of contextual information. Because the most important context for this data is to know who was on the floor. Two man data is out-right deceptive because 60% of the contextual information you have in the 5-man data is masked off.