He's not getting sent back down. The purpose of this season is to develop players to be ready to compete for a playoff spot next year. He can't do that in Triple A.
Bring him up and give him as much time as possible to adjust to MLB pitching.
Do not distort Crews's development for a chance that next year he might win Rookie of the Year. Bring him up when he is ready. I think he is ready now. Maybe the team is figuring out who goes to DH now that Winker no longer gives them a R/L platoon. Night Train Lane can move to DH, or can share RF/CF with Crews and Young.
But, no, there is no reason to hold Crews in AAA just on the off-chance that he might win ROY and an extra pick.