Garza allowed 10 hits and four runs over six innings in his last start on Thursday. He has allowed a National League-high 120 hits in 99 innings this season.
The Brewers called up reliever Corey Knebel to replace Garza on the roster. Rookie Tyler Cravy, who has made one relief appearance since being called up last week, will take Garza's spot in the rotation.
Garza has a 5.55 ERA and 1.545 WHIP in 16 starts this season. The Brewers have the worst record in the NL Central, 18.5 games behind the MLB-best St. Louis Cardinals.
- Dan Gartland