Duke misses Ryan Kelly's defense most

When Ryan Kelly suffered a foot injury Jan. 8 at Clemson, it was casually assumed that Duke would miss his offense more than anything. After all, Kelly's versatility on the offensive end — his ability, at 6-foot-11, to knock down shots from the perimeter — had long been his greatest strength. He was the perfect hybrid four to play alongside Mason Plumlee, who benefitted from the extra space vacated by Kelly's extension on the perimeter. Plus, Ryan Kelly, lockdown defender? That reputation did not precede him.

RealGM's Dan Hanner crunched the comparative numbers for a handful of injury-riddled teams, and what he found about Duke was not exactly what you'd expect. Yes, Duke's offense has taken a slight dip without Kelly. But — turns out — his impact has been felt far more acutely on defense, where the Blue Devils have taken a verifiable adjusted efficiency nosedive — from 82.4 points per game allowed to 95.7.

From Dan:

That’s probably too big a drop off to be permanent, and Duke’s horrific performance at Miami felt like a once-per-season collapse, not a permanent sign of bad things to come. But I think it is informative how Mike Krzyzewski is allocating playing time with Kelly out. While Amile Jefferson has seen his percentage of minutes increase from 21 percent to 58 percent in the four games Kelly has been out, the second biggest beneficiary of playing time is actually Mason Plumlee. And this worries me a little bit if I’m Duke. Plumlee has been playing 96 percent of Duke’s minutes since Ryan Kelly has been out, and Krzyzewski seems hesitant to ever take him out. I worry that all those minutes are having a negative impact on Plumlee’s energy level. Plumlee’s ORtg was 115 prior to Kelly going down, and has been just 95 in the four games since Kelly went down. Some of that is due to the tougher ACC defenses Plumlee has faced, but you have to wonder if the lack of rest time is hurting Plumlee’s overall performance.

That last part is worth noting. No only does Kelly's absence make things more difficult for Plumlee when he's on the floor, it also requires him to be on the floor more. That's more minutes, more defensive attention and less room to operate. If he's tired, you can understand why, and you can understand why Kelly's absence would affect Plumlee most noticeably.

But we should also be praising Kelly's defense, too. You can see why Kelly's reputation as a defensive stopper is practically non-existent -- before this season, he really wasn't one. Besides, it's not like we're dealing with Dwight Howard. But for 6-foot-11 Kelly moves well, maintains great defensive position, can guard a variety of players, and provides plenty of that nigh-invisible glue that holds disparate defensive parts together. The Blue Devils can't get him back in the lineup soon enough.

(Hat tip: Luke Winn)