Ah, hitting dat
timvp with the ol' 1-2 hezi step-back
If (or when) the playoffs become unattainable, I'd be on the side of trading one or both -- starting with DeRozan, if we're being honest.
I think DeRozan has value if the Spurs are making a push for the playoffs. He also has enough value that you don't trade him for nothing or pay to trade him away. (Ironically, judging by the fact that he's been a net negative 17 out of 18 times or whatever the number is right now, he also has value as part of a tank -- but I'll ignore that.)
But, yeah, I'm totally on board with trading them for positive value. You might as well keep them if all you can get is a second rounder or something like that but if you can get positive assets, I wouldn't protest.
The only thing I would caution would be to fall into a sunk cost fallacy. "We traded Nephew for DeRozan so we have to trade DeRozan before letting him walk" is bad logic. I'm okay with letting him walk in principle. That doesn't bother me at all if the alternatives aren't in San Antonio's favor.