Tony, what is a good comp for Lowther? Seems like "deceptive" lefties seem to find the major leagues a problem, generally, to me. Guys like a Tyler Mahle in Cincy may not fit the Lowther offerings exactly, but it's close.
Guys like Lowther have to prove it level by level and I am eager to see what he can do in the majors. Will have to see if we sign anyone like a Tommy Milone again this offseason to push off Lowther's opportunity by a starter or two.
If I had to bet on better defensive value going forward, I would choose Mountcastle over Stewart. I would think that Mountcastle can play an average to slightly below average LF and won't embarass himself. His best position is probably 1B and his athleticism would be an asset there. There have been many worse corner OFs for the O's, Delmon Young, Trumbo, and of course Jack Cust come to mind.
I'm predicting big things for Lowther. He might not have the most impressive pitch arsenal, but he knows how to pitch.. There are a lot of above average starters who don't throw 95+ and a lot of guys with electric arms who never have a major league career. I wouldn't be surprised to see him have the best career of this crop of O's pitching prospects.