The success of the Milwaukee Bucks last season was a surprise to most of the NBA, and it all started with their defense. The Bucks anchored the second best defense in the league under a hyper-aggressive trapping scheme that involved a ton of switching and overloading the strong-side on pick-and-rolls. Their manic style proved to be successful as it powered the young Milwaukee team to 41 wins, a major improvement over their NBA-worst 15 wins the previous season. 

For every step forward the Bucks took last season, they have taken two steps backward this year. A lot of their problems trace back to the addition of Greg Monroe and Jabari Parker into the starting lineup. 

For starters, Monroe has not been able to execute the scheme nearly as well as John Henson or Zaza Pachulia. When defending pick-and-rolls, he is asked to come up a few feet below the pick and shadow the ball-handler until the next action. Monroe has been extremely slow in open-space, and the Bucks have been really bad at rotating to the rim when Monroe fails to recover back to his man.

A lot of this has to do with familiarity within the system. In order to switch effectively in the NBA, you need pristine communication and effort. Successful execution requires playing with a high IQ and knowing where your next rotation needs to be. There have been numerous occasions this season where a Bucks defender just gets lost in the switching havoc.

Take this simple hand-off action from the Spurs:

A communication breakdown between Parker and Monroe leads to a wide-open lane to the rim for Kawhi Leonard. The attentive help-defense that Milwaukee once thrived on is now nowhere to be seen.

The Bucks love to send help to the strong side on pick-and-rolls to wall off any driving lanes. This leaves shooters wide open on the weak-side, calling for Milwaukee defenders to recover and rotate on a dime. Last season they executed those chaotic rotations well, holding opponents to just 37% shooting from the corners. This year opposing teams are killing the Bucks in the corners, shooting 46% on corners threes, the highest mark in the league given by any defense.

Parker is essentially still a rookie, and he has shown very little defensive instinct. Playing as the small-ball 4 in a lot of Milwaukee lineups, Jabari finds himself as the last line of defense in a lot of help situations. Teams are feasting on him. 

It’s not like Milwaukee was playing some defensive stud at the 4 when their defense was at an elite level. A lot of those minutes went to Jared Dudley, Ersan Illyasova, and some Giannis Antetokounmpo, the former two now playing for different teams. Jabari is a slightly better athlete than Dudley, but he has looked clueless when trying to execute the scheme. Dudley played with a high IQ and a keen understanding of where to be in the rotation. Milwaukee was the league leader in turnovers forced last season mainly because of their obedient rotations on the perimeter.

Opposing big-men will feast on the offensive boards when Parker is guarding them. He hasn’t been attentive in boxing out, especially off of a switch. Watch this failed box-out on LaMarcus Aldridge when Antetokounmpo rotates over to stop the drive:

Milwaukee has adjusted recently by having Parker defend the small forward on more nights, while Antetokounmpo takes the other big-man. It hasn’t been very successful though, as he hasn’t yet shown the foot-speed to keep up with most NBA wings moving side-to-side. The lack of size with either option has also exposed the Buck’s inability to rebound the ball. Right now they are the worst defensive rebounding team in the NBA. Wasn’t Greg Monroe supposed to shore up this problem?

A lot of the drop-off comes with the league learning how to attack a particular scheme, as well as the addition of two new starters and the overall youth of the roster. The Bucks remain extremely talented, but when Jabari Parker and Greg Monroe are manning your front-line, playing a super-aggressive defense is probably not ideal.