Think you're reading way too much into this.
Ersson is a medical staff decision, probably got an optimistic assessment, then a correction a couple days later.
They don't interfere with Torts game lineup decisions, where Briere comes in is decisions who to call up and send down, b/c that impacts the Cap, waiver issues, etc.
I'm sure with someone like Drysdale they discuss short-term v long-term, Zamula is better right now but they have to find out whether they can fix Drysdale or have to move on, which means you have to play him at some point.