John B
Watch this entire video and tell me his defense is good with a straight face.
He's slow footed, and lazy on close outs. He's not even putting his hand up when he runs to his guy! Defending 3's is arguably the Spurs' kryptonite. Jalen was put on skates in one play in the video. His hips are so stiff, he gets blown by so easily.
Jalen is more like a center on defense. If we're thinking of him as a small ball 5, that's fine. Any other way and we may be looking at a continuation of last year on defense.
No doubt he is talented on offense. And if that's what the Spurs see as something special, then go for it. If he has no character concerns, then go for it. But he has a lot of work to do on defense, and it may be possible that he'll just be a liability on that end and his team will have to find a way to mask it.