Mathias was recalled by the Brewers on Monday.
Mathias has yet to appear in the majors, but he'll join the Brewers' 30-man roster to play a bench role as part of a string of transactions. The 26-year-old spent the 2019 season at Triple-A Columbus, where he recorded a career-high .797 OPS with 12 home runs, 59 RBI and 13 stolen bases over 115 games, but he's unlikely to see significant playing time in Milwaukee.