What the Boston Celtics need to clean up on the defensive end

With four games under their belt, the Celtics seem to be on the right track before the season starts in next Wednesday.  The young guys have impressed, the offense is humming, and a rotation is developing.  However, there's still work to do.  Brad Stevens has talked about a few things to clean up and after the Knicks game on Friday, I think that one of the points of emphasis going into back-to-back rematches against both New York teams will be on defense, specifically around the rim and rebounding.

It's a small sample size, but the Celtics have been hammered inside during the preseason.  They're 8th in the league in FGA inside of 5 feet, but they're doing a decent job contesting those shots.  They don't have an intimidating force in their stable of bigs, but they're 5th in blocks.  However, they're 5th in offensive rebounds allowed and at times, they've looked lost in rotation and given up easy looks at the rim.  Again, some of that can be chalked up to the European travel and the fact that Boston was missing key defensive players in both games, but it's something to keep in mind.

Defensively, their system is not unlike most NBA teams.  They ICE a lot of PnR's to the sideline, overload the ball side of the court, and rely on the weak side defender to either challenge a perimeter shot if the ball is reversed or cover the block.  Here's a good example from Madrid:

After Avery Bradley fights through his screen and forces the offense to reset, Isaiah Thomas and David Lee ICE a pick to the sideline.  That keeps the ball handler from penetrating the paint, but just as important, check out the awareness on the weak side.  Jae Crowder creeps into the paint, ready to defend the roll man.  Kelly Olynyk is ultimately responsible for defending the roll if a pass gets through.  The Celtics force a very bad shot as the shot clock trickles down.

Here are the young guys plus Sully executing practically the same defensive principles.  Jared's right there as Galloway turns the corner and Jordan Mickey slides down to cover Kevin Seraphin.

There were several moments like that against the Knicks where that weak side D was tested.  New York has a few young slashing type wings on their roster and they run a lot of dribble hand offs and off balls screens to get them free.  Earlier in the game, Crowder overplays Cleanthony Early's cut and gets beat.  However, Jared Sullinger does a good job switching off, guiding Early to his right hand, and forcing him into Tyler Zeller's block.  Evan Turner has his head on a swivel just in case the ball gets dumped down to Derrick Williams or kicked out to Langston Galloway.

I love this clip.  Unfortunately, GIFs don't have sound but live, you can hear Crowder yelling out "I've got baseline!  I've got baseline!" as Carmelo Anthony posts him up.  You can see him get square up his footwork to force Melo into help.  Anthony obliges, turns toward his left shoulder, and is met by Amir Johnson's verticality.  That won't go down as a block, but it's a great example of good team defense and knowing a player's tendencies.

But you can't always be perfect.  Here's early coming off a curl pick.  Jonas Jerebko is beat and he expects R.J. Hunter to pick up Early, well, earlier.  In kind, Hunter's hoping that Zeller will challenge the dunk.  This is what the preseason is for.  It's one missed coverage that will get ironed out as the season progresses.

Just one more.  After the game, Stevens talked about how Boston looked lethargic at Madison Square Garden and didn't match New York's intensity.  A diagonal pass through the paint like this from Jose Calderon to Kyle O'Quinn shouldn't happen.

My guess is that Stevens will trade a few mistakes on the weak side if they can control the ball side of the opposing offense.  Again, it's the preseason, but the team is 6th in defensive rating at 93.9 points per 100 possessions and they're sporting the second best assist-to-turnover ratio at 1.64 and are 11th at forcing turnovers.  Clean up a few mistakes here and there and we really could be talking about this team being one of the league's elite defensive squads.