4) Jo Adell
It's now or never for Jo Adell. There's really nothing else to say. Adell has yet to prove himself so far in his four MLB seasons, and that's a major problem for the former first round pick. The worst part about this situation is Adell is out of options and doesn't have a spot locked in on this team.
Even if the Angels don't make any additions, Adell looks like the team's fourth outfielder. He'd still play a good amount and could even be a platoon option with Mickey Moniak in right field, but his path to playing everyday is not an easy one to see. Moniak, Mike Trout, and Taylor Ward appear to be the outfield trio, and the DH spot would presumably go to Brandon Drury most of the time with Luis Rengifo playing a bulk of the second base.
It'll be hard for him to prove himself from the jump, but Adell will get some starts sprinkled in and when injuries come he could easily find himself in the lineup everyday. With how often Mike Trout has been getting hurt, Adell should be plenty prepared.
Adell proving himself would be great for the Angels as he'd give them another building block to pencil into their future plans. He hasn't shown it at the MLB level consistently, but we all know Adell has the tools necessary to be a really good player. If he fails to elevate his game, his time with this organization could end sooner than later.