Here is a quick thought on Zach Britton.
If the Orioles were not going to have him on the opening day roster, and they did not, they should not call him now if they need another starter due to Brian Matusz's back injury.
In terms of Britton, that should just not change anything. I think the O's should stick to Plan A and call him up later.
If needed, they can find someone to add to the rotation and there are only four dates in April when they need a fifth starter anyway.
Let Britton get his first few starts in the minors as planned. His day will come and it's likely going to be soon.