The Valuing of defense: Part 2, Part 3, Part 4
The under appreciating of NBA players relative short primes, or common post age 30 declines, might be seen as a hobbyhorse of mine around here, but its something that has been very important - in a negative way - to our franchise, in failed signings such as Ben Wallace, Carlos Boozer, and Rip Hamilton. All these players have burned us, very much simply due to age decline.
Let's just look at two graphs from the piece before I run on any more (bigger versions in the links):

The APM based curve corresponds nicely to other studies. Players are often already in the early stages of decline (late prime) by 30 and take a severe nose dive after 32.

But here is something interesting. Defensive impact doesn't peak till much later, around 30, and doesn't tail off that badly till even 34 or beyond. If we think of elder statesman defenders like Tim Duncan, Kevin Garnett, Dikembe Mutombo affecting shots into his late 30s, or even Kurt Thomas plugging away admirably for us a few years ago, I think this analysis finds a lot of common sense at the eye test level.
You cannot teach size, and athletic erosion is going to affect precision based offensive skills, and also notably, smaller perimeter players (sorry BG), much more egregiously than it will affect big defensive specialists.
Relatedly, this site is very high on Taj Gibson (as most adv metrics), awarding him 6th man of the Year and 2nd Team All Defensive for his impacts in that area last year. It might give us some more food for thought on how fast we want to breakup up our frontcourt defensive tandem. Though Taj is soon heading into his 30s (like Afflalo and Melo) his particular specialty gives good reason to think he may remain at a higher impact level than they will, and will resist decline longer. Therefore, it should be our absolute last resort to move him, and if we can hang on to him, *and* acquire offensive upgrades, the future looks bright indeed.
Sixth Man of the Year – Taj Gibson (CHI)- A defensive stalwart winning this award? Have we lost our minds? Thanks to playing 2300 minutes with the tenth best Defensive RAPM in the entire NBA, Mr. Gibson provided over 10 of the Bulls wins according to SWAgR. That is mighty fine SWAgR off the bench. Facing the loss of Derrick Rose and eventually Luol Deng, Taj greatly upped his offensive usage from 18 to 23, while also tallying career high true shooting. With him on the court, the Bulls already stellar defense buckled down even tighter and their offense was better, too; the Bulls net rating improved by 4.1 points when he played. His 13 points, 7 boards and 1.4 blocks in 29 minutes per night don’t look shabby, and for all that, congratulations Taj Gibson! You are the inaugural gotBuckets.com Sixth Man of the Year!
Taj Gibson – He already warranted gotbuckets sixth man of the year award, as according to SWAgR, he was the NBA’s fifth most damaging defensive force this season, gaining the Bulls seven victories with his bucket-denying presence. -GotBuckets.AllDefenseTeams
















