Primo resembles a younger Derrick White with a better jump shot
When looking at the current roster, Derrick White is the one that strikes me as being most in danger after Primo's selection in the draft, even if that danger is not necessarily immediate. Although White is likely one of the best players on the team, he's now 27 years old and is likely close to reaching his ceiling.
While a player like Walker could conceivably exist in the same timeline as Primo, I have a much more difficult saying the same for White. He's nearly nine years older than Primo, and by the time Primo is 22 (the same age as Walker), White will be 31 years old.
Furthermore, when comparing White and Primo when they first entered the league, their skillsets are very similar to one another. White was touted as a good-sized, versatile scorer that is capable of making plays for others. He was also obviously known to be a disruptive defender with a great feel for the game on both ends of the floor.
While Primo is still quite raw, as he's only 18 years old, I see several similarities in his game as he's entering the league. He's a good scorer in the pick-and-roll, can shoot the three well, seems to have upside as a defender, and appears to have impressive basketball IQ for his age.
By far the biggest difference between the two players is their age coming into the league. White came into the league at 23 years old, whereas Primo will be entering as the youngest player in the league at only 18. He will have just over four full seasons of professional experience under his belt by the time he's the same age that White was when he was a rookie.
In that same vein, he's going to have four full seasons more of the Spurs' strength and conditioning training, in-game experience, and film studying. Assuming Primo's basketball IQ serves him in the same way it did White, and he doesn't have any major injury setbacks along the way, it's very reasonable to think that he could become a more skilled and athletic version of White.
Primo may not have been the selection that many Spurs fans were expecting, but if the Spurs can work their developmental magic on him, he could become a true centerpiece for the organization.