Alperen Sengun is digesting a challenging new shot diet

If you haven’t tuned in to the ascendent Houston Rockets this year, let me paint you a picture.

Your typical Rockets defensive possession: a group of demonic hyper-athletes bully your favorite player into turning the ball over.

Your typical Rockets offensive possession: young star center Alperen Sengun stands at the elbow, four teammates frozen in place, while coach Ime Udoka bellows in Turkish for Sengun to man up and cook his defender.

For every bit of Sengun’s gains as a defender, we’ve seen unexpected declines in Sengun’s performance at the offensive end. This oddity deserves a deeper look. Grab some baklava and dive in with me.

All data below through Thursday, Jan 3rd.

What’s causing this shift?

Shot composition and type have changed dramatically for Sengun this season. He’s being asked to create more of his offense himself, and so far the additional creation appears to cost him some of his efficient productivity. Basketball Reference’s true shooting, a metric that adjusts efficiency to incorporate the values of threes and free throws, have Sengun down at 54.8%, a career-worst mark.

Using NBA.com shooting data, we can isolate Sengun’s shot profile by the time he’s held the ball and the amount of dribbles he’s used. While an imperfect way to quantify self-creation, it does offer a glimpse into the degree of difficulty.

Sengun’s share of quick shots (defined as <2 seconds with the ball) reduced 9% year-over-year. He’s taking 11% more of his two pointers after 3+ dribbles compared to last season, making roughly the same rate on those attempts.

He struggles with a bad combination of fewer “easy” shots and shooting worse on those looks; Sengun’s fallen from 58% on shots with under 3 dribbles last season to 53% this year. For shots where he holds the ball less than two seconds, his finishing fell 11% year-over-year.

While NBA.com doesn’t allow you to group these stats with other filters, you can see the outlines of this in the location breakouts. Sengun takes roughly the same field goal attempts at the rim (6.8 this year vs 7.1 last) and converts at similar rates. The largest contributor to his decline? Attempts in the non-restricted area paint. Sengun again takes a similar quantity, but now he shoots an abysmal 39.9% on 5.8 attempts, combined to 48% last season. He’s in rough company: among bigs with at least two attempts a game from this area, only Evan Mobley shoots worse.

Sengun has the third-worst decline in YoY efficiency, trailing only Ivica Zubac (who doubled his attempts from last year) and Bam Adebayo (who is fighting the Jimmy Butler experience in Miami).

His play-types have changed demonstrably

We can also leverage the great work of NBA RAPM, a stats website that aggregates multiple sources to provide a clean look into player production. Here, we can isolate specific types of offensive usage and compare them to league wide production and Sengun’s own career. Looking at the change in play type usage neatly visualizes Sengun’s new offensive function, and points per possession normalizes his output to make it comparable to other players regardless of pace.

First, the good news. Isolations per game, where Sengun takes his defender on by himself, increased from 2.2 possessions to 3.1, and points per possession increased from 0.82(24th percentile) to 0.96 (76th percentile). Post-up volume stayed the same, but efficiency (57.6% vs 61.9%) and PPP (0.96 to 1.07) improved. He’s increasing his self-creation and improving his output.

He struggles to drive efficient offense as the roll man in the pick-and-roll. Roll man volume dropped from 5.4 possessions per game to 4, and true shooting plummeted from 61% to 52%. As the roll man, Sengun produces 0.98 points per possession, 14th percentile for the entire league. While Sengun has never been above-average by this metric, 52% TS would be a career-worst.

He’s added 1.8 possessions per game of spot up shooting as a thought experiment, and thus far, the results scream for a change in plan. His spot-ups produce 0.82 PPP, good for 14th percentile leaguewide. Much of this likely stems from his occasional three-pointer, which go in 22% of the time and may need to go back into the toolbox for now.

Another big decline appears in transition volume and efficiency. Transition possessions per game dropped from 2.1 to 1.7, but most alarmingly, true shooting fell from 71% to 47%. I’m not sure if this could be a schematic change for Al P, as he’s taken on more defensive responsibilities, but no matter the cause 47% TS on transition opportunities drags him down like an anchor. Last year, Sengun’s 1.27 PPP put him in the 84th percentile; now, his 0.74 PPP puts him at the 1st percentile, nearly worst in the entire league.

What it looks like in practice

Bring all these threads together, and you have the clear profile of a young star learning how to handle a more difficult shot diet. Two examples of Sengun misses in his recent game against Dallas neatly highlight the challenges and the potential for improvement.

Take this possession, pulled from the NBA’s box score video recaps. Sengun catches a pass from Jalen Green on the roll, gathers, and tosses up his beloved hook shot right outside the restricted area.

It rims out, but this is a good and decisive look by Sengun that you like to see (especially the rare appearance of a Jalen Green playmaking instinct). Over the course of a full season, you imagine the efficiency of these shots to level out.

However, possessions like the one below are the ones where you see the strain most clearly.

He gets the ball outside the three point line with 17 on the shot clock, drives headfirst into a capable defender in Dereck Lively, and tosses up a no-hope shotput that careens off the front rim. You’ll notice during this drive that no Rocket player moves into a passing lane other than Fred Van Vleet’s late scramble.

These iso, roast his ass possessions are the purview of superstars, and it will be fascinating to see how Sengun uses them as the year goes on.

What to watch for the rest of the year

Projecting a bounce back for Sengun’s efficiency is a tricky beast. Certain aspects of his offense seem poised for a bounce back, as he’s unlikely to be a sub-40% shooter in the paint for the year. Others, like a dramatic reduction in transition opportunities and efficiency, may be schematic changes that he cannot address.

Houston mostly treats Sengun like the franchise building block, and offers him the type of shot diet that a star enjoys. They can offer this usage while still making life easier for him; no movement meandering drives from beyond the three point line should be a neon red warning sign. A concerted effort to improve his finishing as the roll man, and a team-wide effort to move without the ball will only help rebuild Sengun’s efficiency and unjam an often-clogged Rockets offense.

We saw the outlines of an offensive star last season, with glimpses still visible this year. Sengun has the leeway and the skills to get back there; I cannot wait to watch.