Fiers, 28, has bounced back and forth between Triple-A and the big leagues this season after going 9-10 with a 3.74 ERA in 22 starts and one relief appearance for Milwaukee in 2012. He's gone 1-4 with a 7.25 ERA in three starts and eight big-league relief outings this year. In Triple-A, Fiers went 1-2 with a 2.20 ERA in five starts.
The Brewers currently rank dead last in baseball with a 5.14 ERA from their starters. Right-hander Kyle Lohse, who signed a three-year contract during spring training, is the team's only starter with a sub-4.40 ERA so far this year.
At 28-39, Milwaukee has the fourth-worst record in MLB. They recently lost Ryan Braun to a thumb injury as well.