4) Davis Daniel is behind too many better options on the Angels roster
The Angels have five starters set in stone but the sixth starter spot is wide open. Someone like Tucker Davidson could have an outside shot, but Griffin Canning and Chase Silseth are probably the favorites heading into Spring Training. The Angels could (and should) of course just sign a free agent to take that sixth starter spot.
The Angels also have pitchers like Chris Rodriguez and Kenny Rosenberg who won't be on the Opening Day roster but could be ahead of Davis Daniel on the 40-man roster.
I'm surprised Daniel has lasted as long as he has on the 40-man, but if the Angels sign another player he could be the pitcher on the chopping block. There's a very good chance he clears waivers and then there's no harm no foul there.
Daniel is 25 and hasn't appeared in a big league game yet and had a 4.19 ERA in 21 starts in AAA. He's on the 40-man roster solely as starting pitching depth, but the Angels have plenty of better options.