Many sources peg the Spurs as needing bigs, but they're never clear or misunderstand what bigs are needed. We don't need centers that are not stretch-capable and even then it's not an area of priority.
The Spurs need: defensive size/athleticism at the 3-4 who can shoot, shooters in general, and playmakers. The only playmaker on the squad is Derrick White, by which I mean a guy who can see the floor outside of mechanical sets. Murray is on the Parker track -- not a natural playmaker, but learning where guys will be and can certainly run those. Manu was able to rip defenses up because he was a natural playmaker.
I don't really know who a stretch-four is in this draft. Mostly there are stretch-fives, but then these categories are difficult to cement nowadays. Samanic has some stretch 3/4 capability, but 1) we need a bruiser type who can corral rebounds, 2) he's not trustworthy (yet). I think Poeltl's fine, but he does reduce what is possible with the rest of the lineup. I think Eubanks is very serviceable as a backup big and is flashing some jumpshooting ability. I don't expect Dieng to stay. Something about not actually playing the dude when you sign him.
So... for that stretch three-four, a guy like Trey Murphy is very interesting. I don't think he's worth the #12, however, and know he'll be gone by our 2nd round pick. He's a very tall and long 3-and-D type who unfortunately is a bad rebounder.
There is some possibility of Sengun becoming that stretch-four and I actually think he will. Barring those choices, it's not really clear who is there at #12 that helps, which is why I'm looking at guys like Giddey (playmaking) and Kispert (shooting) instead.
EDIT: I had been going away from Wagner due to Samanic overlap, but he's also that stretch power wing that might work in this regard.