Brubaker was optioned to Triple-A Indianapolis on Monday, Rob Biertempfel of The Athletic reports.
Brubaker was able to spend the first portion of spring training working with the major-league coaching staff, but he'll now report to Triple-A to prepare to begin the season in the minors. The 26-year-old dealt with a right forearm strain last season, but it appears as though he'll be fully healthy to start the year as he prepares for his third consecutive season at the Triple-A level.