An outfield of Kepler, Rojas, and Marsh would be among the weakest offensive outfields in baseball. Good defensively, but way below average offensively. I just don't see the team trying that too often.
Rojas needs to improve his offense to play every day. And since he can't throw yet, he is clearly not a defensive option either early in the year. Hopefully by May he is back 100% but we are not there yet.