The Brewers reassigned Brothers to their minor-league camp Monday.
Brothers signed a minor-league deal with the Brewers on Tuesday which includes an invitation to spring training.
Brothers elected free agency Friday, Meghan Montemurro of the Chicago Tribune reports.
Brothers allowed two runs on four walks while retiring just one batter in Saturday's loss to the Giants.
Brothers (3-2) pitched a perfect inning and struck out two, earning the win Saturday versus Arizona.
Brothers (2-1) allowed three runs on two hits across 1.1 innings to take the loss Wednesday against the Brewers. He walked two and struck out two.
Brothers (2-0) pitched a scoreless inning of relief and earned the win Wednesday against the Padres. He struck out two.
Brothers pitched a scoreless inning with two strikeouts to record a hold in Wednesday's win over the Padres.
Brothers allowed one hit and no walks in a scoreless third of an inning to earn the save against the Pirates on Friday.
Brothers (1-0) struck out three batters in an inning of work out of the bullpen and earned the win Saturday against the Reds.