It looks like you don’t need a 5th starter until the 14th and really it looks like you may need the 5th start again for about 10 or so days after that. So, they could keep him down, gain the extra year of service time and he would basically only miss one start.
They could just have the 14th be a BP game.
This was part of my initial thought process. Set the price high now, if they take it, do the deal. If not, we still have him and I believe his value will keep growing well.
As far as being a “core player,” he was voted the team’s most valuable player. That is about as CORE as it gets. Is he a core player on many contenders? That’s a separate question, and depends on the team.
Nothing here to argue with, but if Baumann looks to be healthy, pitching well and successful this spring, I would not be surprised to see him start the year in the rotation or at least once the team needs a 5th starter.