Mullins can't hit lefties as a right handed batter, the disparity in the stats between LHP as RHB and RHP as LHB are pretty significant.
I'd be curious to know if he can hit lefties as a lefthanded batter. If so, he might be able to carve out time as an every day player. I still think he's a 4th outfielder, though. But not a bad 4th outfielder to have.
DJ Stewart might be coming around, though. I like the patience at the plate, too.