Most likely for the immediate future, they are moving Valbuena to 1st and starting Bregman at 1st. They will have to switch things up when Marwin gets back.
Sounds like the softball team I played for in Austin. Most of the 13 on the roster were 55 or older. We had 10 1b/catchers. That said, I get what you were saying. I don't think the return of Marwin will affect things much. Luhnow has said they prefer Marwin to return to his super-utility role rather than everyday player. I think it makes our bench much stronger with him coming off it. He'll still get his ab's.