In my eyes, it's quite likely that either the money or the minutes just aren't there. More likely the minutes.
Lyles has played himself into a bigger contract this year as he can now be seen as a legitimate floor-spacing threat; I also think he looks like he's in better shape than he was last year. LIke
@iowamcnabb suggested, it looks to me like he should get something like 3/$15M, or maybe more in terms of dollars. And he's going to want to get floor time. I don't think he can demand a starting spot, but he's clearly worth rotation minutes. If we sign Sasha, he'll probably feel squeezed and elect to sign elsewhere. The same would apply in the opposite direction - if we sign Lyles, Sasha may have quite a bit less incentive to leave Olympiacos, because even though our MLE will be able to give him a raise, in Europe he's an MVP, and he'd potentially be in danger of falling out of the rotation here. I don't think that would happen, but is it worth the risk?
The way a "both" scenario works, I would guess, would be the Kings moving (or stretching) Richaun and committing to Lyles as our backup C, leaving a slot open in the F rotation for Sasha (i.e. Barnes, Murray, Sasha). Of course, I'm assuming we bring Barnes back, but that seems like at least a decent bet right now.