There should have been a Doc vs Green moment after the last play. I just watched the clip several times and Green was in perfect position for that rebound and he never even came out of his crouch position or raised his arms up. I have no clue what he could have been thinking. If you are under the rim and the ball is coming down, you try to get the ball. Little kids understand that but Jeff Green does not.
I watched the replay, and it looked to me like Green was working to keep Ryan Anderson from being in position to get a rebound. I think that play was on KG—yes, he came over to help on Gordon, but he was still in good rebounding position, and all he had to do was put a body on Davis, or go up and grab the ball himself, and he didn't do either.
I've watched the replay several times now:
http://www.nba.com/video/games/hornets/2013/03/20/0021201013-bos-noh-play3.nba
and yes, Green is properly (and basically successfully) boxing out Anderson from coming from underneath. Remember, the goal in that situation isn't necessarily to 'grab the rebound' - they only needed to prevent a put back.
KG actually did the right moves in the sequence - because Gordon beat Bradley to the right side and drove the paint, KG had to release from Davis (who he'd had blocked at the left elbow) to help contest the shot.
What was supposed to happen when KG released is that Lee, who was standing just outside the paint on the left, should have rotated in to block Davis from crashing.
Three things made this play work:
1) Roberts swung out the the right corner forcing Pierce to setup a full step out from the paint, vacating the right side of the paint. Nothing done wrong by Paul there, it is what it is.
2) Given that, Bradley needed to force Gordon to go to his left, to the overloaded side. You HAVE to show him the left side and overplay the right in that situation. Instead, he tried to square him up and Gordon beat him to his favorite side with the spin move. Once Gordon penetrated, KG had to collapse.
3) Lee forgot to rotate. Davis was able to crash and tip it.
A lot of folks are screaming at KG as if this play was his fault. But the two basic mistakes in the team defense were by Bradley and Lee.
I disagree. I don't think boxing out Anthony Davis was Courtney Lee's assignment.
Garnett didn't move far enough across the paint for Lee to jump down and leave his man wide open spotting up behind the arc. Garnett was in good position to recover to Anthony Davis and box him out. He just didn't do it.
Now if KG moved all the way across to the other side of the paint or rim, then yes, I think it would be Courtney Lee's job to box out Anthony Davis. But Garnett was always in position to recover and box out Davis. He stayed on the same side of the basket + Garnett was in between Davis and the rim. He was only one step away from putting a body on Davis.
It is not like KG went up to challenge the shot and would have been unable to recover to Davis. In that case, again, it is Courtney Lee's assignment.
But the way KG did it, shadowing over to protect the front of the rim left him in good position to both take away that angle on E.Gordon's drive/shot + to recover to his own man once Gordon went down the right hand side of the lane.
I agree with others that it was KG's defensive rebounding error.
On a play earlier in the clock, it is arguable that Lee should not too quickly abandon his man (Vasquez) - but even then, it is normal for the C's to show help & recover in exactly that scenario. But on a last-second play, there is 100% no reason to worry about a carom that goes all the way to the 3PT line. There is no reason at that point to worry about the 3PT shooters at all.
To this point - as Gordon drives, you can see Lee abandon his man anyway - he lets Vasquez move off to the top of the key and instead just stands and watches the play.
Both shooters on each side (Vasquez, Roberts) did the same move - towards mid-court. Pierce actually starts to move a couple of steps with his man, but stops as there is no point. Lee, as mentioned, doesn't follow Vasquez at all.
He stood and watched.
If instead he steps in, it wouldn't take much to have warded Davis off just enough that there would have been no way for him to tip it back in in time.
Rebounding is a crap shoot - you can have great position and great length and elevation and great hands, strength and skill (all of which KG has), but all that only increases your _probability_ of grabbing the rebound. Other players also have those things. And the ball bounces - sometimes in funny ways.
(Not to mention - the ball technically never finished bouncing out of the cylinder!).
But if you execute the _team_ defense in the correct fashion - either by Bradley at the point of attack by not letting Gordon go to his right, or after the shot by Lee rotating in to block Davis, then there is no need to hope for a friendly rebound bounce.
You remove that variable through deterministic action.