LaMarcus Aldridge is a huge defensive liability for the Spurs

The Spurs have a big problem. One of their prized veterans, who has an impecable resume and has been a perfect culture fit for years now, is struggling greatly this season. LaMarcus Aldridge just doesn’t seem to fit anymore and the way his presence appears to be hurting the team has become impossible to ignore.

There could be tough decisions ahead for the coaching staff, because unless something magically changes fast, having Aldridge on the court as much as they have so far would be not only an obvious mistake but one big enough to severely hurt their postseason chances.

The concerns about Aldridge aren’t new and were definitely there before the season. The team did well in the bubble without him, playing a different style, and his potential fit around that new identity was always questionable. The biggest red flags seemed to come on offense, where the Spurs were clearly going faster and more perimeter-centric at a time in which Aldridge had already lost his quickness while not really developing a consistent outside shot. Without shining on that end, however, he’s done well enough. The big man is not a lob threat but can serve as a screener thanks to his ability to pop for open shots and he has made 36 percent of his threes so far. There’s plenty of room for improvement, but the offense still works well enough with him around.

The problem is on defense. San Antonio allows over 116 points per 100 possessions when Aldridge is on the court, a mark that would rank as the second worst in the league. The biggest issue comes at the rim, with opponents shooting over 65 percent in the restricted area when Aldridge is on the court. Opponents also feast from mid-range when Aldridge is around, shooting 48 percent from the in-between area. Both marks are disastrous and sketch a picture of a center who lacks both the athleticism to contest well at the rim and the mobility to be an asset away from the paint.

The Spurs mainly play drop defense in the pick and roll, which means the big man hangs back to discourage penetration and allow the primary defender time to recover. It’s the type of defense most teams with traditional centers use, and it’s designed to prevent shots at the rim (and beyond the arc) by having just two players directly involved in plays instead of triggering several rotations, like the most aggressive schemes. Unfortunately, Aldridge can’t really execute it at this point.

Due to his limited mobility Aldridge has to drop way back to prevent easy blow-bys or lob passes, which leaves opponents with all the room in the world to hit mid-range jumpers and often forces one of his teammates to help. But even while dropping back to the point that he can’t contest pull-ups, Aldridge doesn’t protect the rim. Aggressive ball-handlers simply attack him and finish over or around him.

The issues are not only present in the pick and roll, either. If Aldridge is asked to switch or defend a particularly dangerous pull-up threat on the perimeter, he has no chance of staying with that player. His quickness, which was never elite in the first place, just isn’t there anymore.

Similarly, he has completely lost his second bounce, so knowing that he can’t recover if he contests, he often chooses not to, failing to provide enough help defense. Aldridge ranks fourth on the team in total contested shots at the rim, behind not only Jakob Poeltl but also Dejounte Murray and Keldon Johnson. That lack of a second burst is also causing him all sorts of problems on the boards, where he’s currently posting the worst numbers of his career by far.

It’s not all Aldridge’s fault. The Spurs’ perimeter defense is still porous, especially in the starting lineup and particularly at the wing spots, which expose his issues further. The problem is Aldridge is simply not equipped to erase the mistakes his young teammates make at this point in his career and he happens to play the most important position on defense. Teams can create good defenses around bigs that are a) mobile but not great at protecting the rim, or b) good rim protectors that struggle to move, but not around centers who can’t do either.

Aldridge’s defensive limitations are only made more obvious in contrast with Jakob Poeltl’s excellent play. The same starting lineup that is a complete disaster on defense with Aldridge around (124 defensive rating) is merely mediocre (109 defensive rating) when Poeltl, who has started seven games, is in his place. As we covered before, the bench’s numbers are fantastic, and that’s also partially thanks to Poeltl. Clutch numbers are hard to trust because of how sparse they are, but even then the team has been a train wreck on defense with Aldridge playing and elite with Poeltl on the court.

In short, before Aldridge’s hip issue forced him to miss games, the Spurs have had a borderline elite defensive center playing too little and a terrible one playing too much. The offense that Aldridge provides doesn’t seem to be good enough to make up for his defensive limitations, and those limitations are not likely to disappear since they have been becoming more and more noticeable in recent years. San Antonio has been an abject disaster on defense with Aldridge on the court for three seasons now and while the arrival of DeMar DeRozan and the departure of Kawhi Leonard and Danny Green served as an excuse before, Poeltl’s play next to similarly defensively-challenged teammates has made it clear that Aldridge might have been the biggest culprit all along.

Will the Spurs, who surely know that this is a problem, be proactive in solving it by permanently shelving or even trading Aldridge? It seems unlikely. After all, this is the only star in the Popovich era to pick them in free agency and he was a huge part of their success just years ago. He’s also been graceful at accepting a new role and seems to play with effort. There is some precedent, however, for veterans to be asked to come off the bench. Pau Gasol did it when his defense became problematic and even Tony Parker did it in the last year of his contract. It’s possible it happens again, which could be a good idea. As a 15 to 20 minutes a game backup and as a part of the more mature and stable second unit, he could still be helpful.

Ideally, Aldridge would return from his recent absence rejuvenated, showing the bounce and mobility he had a few years ago and with an even more accurate outside shot, becoming a huge asset for the starting unit. But if that’s nothing more than a pipe dream right now, the Spurs will eventually have to deal with reality.

Aldridge has earned a lot of patience from the franchise, the coaching staff and the fan base with his excellent play from a few years ago, so it’s fine if the Spurs want to be absolutely sure that he can’t turn things around as a cornerstone before demoting him. If things continue to be like they have been so far, however, a change seems unfortunately inevitable.