Lutz needs to go to AA. He is hitting .231 in 250 plate appearances at that level.
He was bouncing back off injury in a lot of his AA ABs last year.
He was hitting very well in the Arizona Fall League last year before he got hurt, and that league is AA at least.
Look at what he's done in his initial exposure in the bigs, which is on the heels of a big spring training.
Add it up, and you've got AAA at least, IMO.
Sometimes a player needs to be challenged in order to rise to the level of his abilities and thrive. Lutz is showing he may be one of those guys. Hit the accelerator, not the brakes, with this kid.