Guarding John Jenkins on the Perimeter

Sometimes life just converges in a nicely satisfying way. On Saturday Kentucky beat Vanderbilt in a terrific game. In the game thread and later in the Vandy DSS I (and others) noted how well Doron Lamb did chasing John Jenkins around the floor and in particular doing a pretty good job of not giving him many open looks from the perimeter. Then on Monday Glenn posted some thoughts about a series of posts that Ken Pomeroy made last week regarding the impact that defenses have on opponents' ability to take and make 3 point field goals.

While doing the video review for the DSS I was even more impressed by how active Lamb was in chasing Jenkins, fighting through screens to stay with him, and generally making sure that the SEC's leading scorer could never get multiple open looks in the game. Lamb didn't do this alone - he occasionally got some help defense from teammates to help slow Jenkins down until he could catch up to him and Michael Kidd-Gilchrist was charged with guarding Jenkins when Lamb was on the bench or at times when Kedren Johnson was in the game (Lamb then guarded Johnson while MKG was on Jenkins). Lamb got the primary assignment though: 95% of the time he was the guy defending one of the best shooters in the country.

It would be tempting to say that Lamb had a bad defensive game - Jenkins did score 18 points and shoot 44.4% (4 of 9) on his threes. But a lot of what Lamb did so well was in preventing shots - an aspect of defense that is more difficult to account for systematically, even for something like the DSS. That's what I want to highlight here.

What I did was watch the Vandy game again, this time keeping my eye on Jenkins when the Commodores were on offense. I took screen grabs of every 3 point FG he attempted as well as every time he received the ball on the perimeter in a number of typical shooting situations - coming off screens, in transition, or curling around after cutting along the baseline. The purpose is to give you some idea of how tightly (or not) Kentucky was able to play him throughout the game.

This first picture shows each of Jenkins' 9 three point attempts as close as I could get to when he started to take each one. I've outlined in the blue the attempts when Lamb was the defender as well as kept a running tally of Jenkins' overall shooting after each shot. You can see that in the first half Jenkins only took 2 shots and missed both and each time a different UK player came out to contest the shot. The only really bad bit of defense by Lamb came on the first make of the game, when Doron went under a screen by Steve Tchiengang allowing a wide open look. It's hard to convey using still images, but the Cats were very active and alert at identifying where Jenkins was on the floor at all times and not letting him get a good look at the basket.

This picture is the one that I think is most interesting: it shows what happened immediately after each time Jenkins received the ball coming off a screen, in transition, or cut along the baseline and curled around to the perimeter but didn't attempt a shot. I've once again outlined in blue the times when Lamb was the defender.

A few things are striking from these plays. First, there was a big adjustment by the Commodores between halves: they ran Jenkins off a lot more screens in the second half and made a more concerted effort to get him the ball in those situations. Second, you can see that Lamb was right on him in 8 of the 11 plays. Notice how often Jenkins is in a shooting position - a few are ball fakes but many times he looked like he really wanted to shoot immediately, but was dissuaded from doing so by the proximity of a Wildcat defender. Most of the time that defender was Doron Lamb.

I would estimate that Lamb prevented Jenkins from attempting at least 2-3 three point shots just by sticking to him through screens. That might have been the difference between Jenkins scoring 18 points and scoring 24 and giving this game a very different look in the final minutes.