Stevenson has exceeded his rookie status, so he's no longer officially a prospect. however, some kind words from Eric Longenhangen at FG about his bat, if not his arm, and his ability to stick as a reserve:
I still like Stevenson’s bat-to-ball skills, speed, and high-effort style of play enough to consider him a big league bench outfielder. I also think he can really only play left field, despite his speed, due to a lack of arm strength. As a lefty bench bat and pinch runner — maybe as a late-inning defensive replacement in left field for Juan Soto, though Michael A. Taylor would just be better at that — he’s rosterable.
https://blogs.fangraphs.com/prospect-limbo-the-best-of-the-2020-post-prospects/I think the arm concerns about Stevenson might be why Taylor still has an expensive place on the roster.
