Last year, the Oklahoma City Thunder made the playoffs and won 50 games on the strength of defense. The Thunder posted a Defensive Rating of 101.6, good for 8th in the NBA. This year, despite an improved offense (jumping from an Offensive Rating of 105.8 last year to 106.1 this year), the Thunder seem to have taken a step back. The reason? The Thunder's defense has been much worse this year, as the team's Defensive Rating has slipped to 104.0. This drop has seen the Thunder's eighth-ranked defense fall all the way down to 17th.
The two main areas where the Thunder is struggling on the defensive end this year are isolation situations and spot-up situations, according to Synergy Sports Technology. The Thunder is giving up .87 points per possession on isos (20th in the NBA) and 1.01 points per possession on spot-up opportunities (21st in the NBA). The most interesting thing is that the Thunder did really well in both of those instances last year, holding teams to .78 points per possession in iso situations (first in the NBA) and .94 points per possession in spot-up situations (fourth in the NBA). Sine the Thunder did not lose any rotation players this past offseason, it is interesting to see such a drop, and this leads to the question, "Is the Thunder's team defense worse, or are the individuals playing worse?"
Interestingly enough, Green is really struggling in the two areas that the Thunder as a whole struggle with. Green allows 1.11 PPP in iso situations (ranking him 215th in the NBA) while allowing 1.16 PPP in spot-up situations (ranking him 247th in the NBA). Green's problem in iso situations is that he is a tweener, playing in between the three and four positions. While this creates mismatches on the offensive end, it leads to problems on the defensive end. Green isn't quick enough to stay with threes, and he is too small to cover fours effectively:
When Green is covering threes, his lack of speed really hurts him. Because of that, Green tends to play off of the ballhandler when he is covering threes, to try and prevent his man from getting to the rim. That is what happens here, but Green gives way too much room and allows Rudy Gay to knock down the jumper.
In this clip, you see what happens when Green tries to play up on threes--they simply drive by him. Here, Green is up on Michael Beasley, and Beasley simply gets him on his hip and hits the layup.
While Green struggles with small forwards' quickness and shooting ability, he struggles with the size and strength of four-men:
Here, Al Horford makes the catch at the top of the key and simply goes at Green, playing bully basketball. Green is unable to keep Horford from getting to the rim, and Horford hits the layup.
In spot-up situations Green struggles because he tends to wonder from his man a bit. When that happens, his closeouts become very weak:
Here, DeShawn Stevenson uses an off-ball screen set by Green's man. Green shows and helps, keeping Stevenson from getting to the rim. This is good initial defense, but he never recovers to his man, Shawn Marion, until he gets the basketball. When Green returns to Marion, he does so with his hands down, allowing Marion to hit the jumper over him rather easily.
Green has really struggled on the defensive end, but one player struggling on the defensive end isn't responsible for the kind of drop the Thunder has seen in its defensive metrics this year. For six of your top seven players to improve their defensive rating and still have the team defensive rating as a whole decrease, you have to be playing some bad defense. This is the case with the Thunder, especially in ISO sets:
Here, Sefolosha is playing man-to-man defense against Marco Belinelli. Belinelli is able to get by Sefolosha, but that is only the first mistake made by the defense. Durant shows quickly but returns to his man, allowing Belinelli to continue his attack to the basket. Belinelli keeps going towards the rim, and late help from Ibaka allows him to hit the layup easily. There are three mistakes here: Sefolosha can't let his man go middle, Durant needs to hold his help a second longer and Ibaka needs to step up quicker. If any of those three things happen, the Thunder doesn't allow a layup.
In this clip, you see everyone paying close attention to their man off of the basketball, and that allows Kyle Lowry to get to the rim easily and finish the wide-open layup. The fatal mistake on this possession comes from Durant, who fails to maintain eye contact with both his man and the ball. So as Lowry attacks the basket, Durant doesn't even see it, and he can't help because of it.
Finally, here Daniel Gibson makes the catch and attacks the middle of court. Ibaka has a chance to come over, help, and block the shot, but instead he stands there and watches as Gibson knocks down the floater.
If you are watching the Thunder on defense, you definitely notice a difference between last year's defense to this year's defense. There isn't really much of an emphasis on team defense. Instead, guys seem to be too focused on their own men, preventing "their guys" to score. The problem is that isn't how successful defense is played. So while teams have been able to take advantage of Green on the defensive end, the bigger worry is the Thunder's team defense, especially in isolation situations.
Sebastian Pruiti is an author of Basketball Prospectus.
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