A few days ago, we laid out the numbers on the Kings' isolation defense, which is surprisingly good, considering the team's defense as a whole is not. Second-year big man Jason Thompson was among the three surprisingly amazing iso defenders on the team last season. J.T. ranked No. 19 among all isolation defenders last season, holding opponents to 0.66 points per possession.
What about the rest of J.T.'s defense? When Thompson came into the league, he looked like an able defender -- long, strong, high-energy, tough, fairly agile/dexterous. But the team's defense that rookie season was so abominable nothing positive could be gleaned. It improved quite a bit this season on the team level, and with two years of observation and one year of hard play-by-play data (via Synergy), I think we can start making reasonable assessment of J.T.'s defense.
So, what's the verdict? Is Jason Thompson a good defender?
On the year, Thompson had the best unadjusted defensive plus-minus of any regular Kings bigs. (That'd be Spencer Hawes, Carl Landry and Jon Brockman.) The Kings defense was 1.6 points per 100 possessions better with J.T. on the floor than when he was not. As the two highest-minute big men (Thompson and Hawes) rotated between the starting line-up and bench, unadjusted plus-minus is less problematic than it normally would be. That the team would be better defensive with Thompson on the floor isn't surprising.
But Synergy's data lets us go deeper.
So we know about J.T.'s iso defense: it was damn good this season. What about in the post, where he defended 203 plays? Opponets scored 0.9 points per possessions against J.T. there. That's about middle of the pack for the NBA. Opponents shot 47% on J.T. in the post, and he committed a shooting foul on 11% of these plays.
Defending spot-up shots: J.T. is awful, giving up 1.11 points per possession, ranked 319 in the league. Opponents shoot 55% (eFG) against J.T. on spot-ups.
There isn't enough data to draw any sort of conclusions on the other play types, though the limited data suggests he's not bad guarding the pick-and-roll. If we move back to macro, we know he has a positive effect on the team's defensive rebounding: not only is he a good rebounder, but the team rebounds better as a whole when he's on the floor. (This extends beyond his own offering.)
J.T. became a better shotblocker this season. He had 59 blocks his rookie year, and 73 this season in roughly the same number of minutes. His steals and, of course, fouls decreased. He still fouls too much (more than four per 36 minutes) and still isn't a very good shotblocker (2.3% block rate). But progress is progress.
In total, I think we can call J.T. a "not bad" defender. Maybe even "good." Although he's getting challenged in the post and killed on chase-outs, he does enough good things in isolation defense to make up for it. He could certainly stand to improve, like all the Kings. But he's not the biggest problem, that's for sure.
Later this week, for comparison's sake, we'll look at Spencer Hawes.