I'm a big advocate of not Peter Principle'ing pitchers. If they find their niche after years of inconsistent results it's probably because they are well suited for said niche. Not because they suddenly learned how to pitch.
Let's say Britton is a 3.25 ERA reliever. That means he's probably a 4.25 starter, and the O's already have more than five 4.25 ERA starters. Everyone is better in relief, in short stints, going through the lineup once or less.