diaz has definitely shown skill. rsing him would be unconventional, since we lack big depth, but could make some sense since he's shown a lot more offensively than defensively.
it'd be nice to trade out johnson for another big. but i don't know if it's absolutely necc. in order to rs diaz. they'd have 3 bigs to throw at one position without him. gippy should eat about 25 of those minutes himself.
if you don't rs diaz, you have 4 bigs, none of whom are good enough to justify putting a guard on the bench to play two at a time. either you're talking about diaz continuing to sit on the bench or you're talking about him giving you 15 minutes/game while your other two bigs that are (prolly) about equally as effective sit on the bench. either way, you don't lose a ton by rsing him unless he comes out of the summer vastly improved.