Decision #2: Keeping Zach Collins as the backup center
For the time being, Jakob Poeltl will remain as the team's starting 5, leaving the Spurs to sort through their backup center options. Zach Collins is the incumbent backup center, but Gorgui Dieng and Isaiah Roby are both viable options in their own right, and perhaps better ones. Collins has the most offensive potential of the three players, but he's also the worst defender. To his credit, he has been more aggressive shooting from outside, trying to become a true stretch five, but has shot the ball poorly thus far, leaving the door open for Dieng.
Although Dieng is less talented, he's carved out a niche as a capable rim protector, rebounder, and floor spacer. Additionally, having a more proven stretch five who's also shot it well in preseason and has displayed solid passing gives him a chance to earn regular minutes at center. This is despite him being signed as a third-string option at the position.
Meanwhile, Roby mostly played small-ball center in Oklahoma City, and he'd allow Popovich to get weird with lineups. How about a Keldon Johnson, Keita Bates-Diop, and Roby frontcourt? Don't like that? What about Johnson, Sochan, and Roby? That's a better unit, and it has defensive versatility with their frontcourt all being similar in size, allowing them to switch some. Roby isn't much of a rim protector but is capable of defending on the perimeter. He's also the best shooter in the group and runs the floor like a wing.
The Spurs shouldn't be married to having Collins as the team's second-unit center, especially with other intriguing options on the roster. That said, I expect Collins to get the lion's share of the non-Poeltl center minutes and possibly even start when Poeltl is eventually traded. Either way, Spurs fans should expect to see a fair amount of Collins, even if he might not be the team's best backup center option.