I see Thomas working on CF over the winter. He does not seems to run the outfield the way a CF should. He hits. I see Robles playing in AAA the way he should, showing talent. There's hope for Robles. Thomas and Robles can compete in Spring Training and in April. One wins and the other shares time in LF. That's good.
Stevenson? As suggested above, there is no reason to expect Stevenson to be anything more than a 4th OF, a guy who is adequate when a regular is injured. If Robles shows he can hit major league pitching, then either he or Thomas are the 4th, and Stevenson makes a great OF version of Adrian Sanchez. Good suggestion, JCA. (Incidentally, Sanchez looked good with Rochester last night. Didn't see Noll, who was tossed in the first inning)