Ryan Braun indicated that he'd be open to moving to first base in a radio interview with WTMJ-AM this week.
It's probably not something the Brewers will discuss this winter, though it could be a possibility come 2019. It also might become a factor if Braun's name comes up in trade talks again. He was rumored to be going to the Dodgers in Aug. 2016, and there was again some speculation there in the spring. Braun now has full no-trade protection, and while he still might be willing to go to the Dodgers, it doesn't appear that he's interested in playing anywhere else.