The team also announced Thursday that Chase Anderson will open the season in the rotation. Anderson joins an all right-handed starting five of Junior Guerra, Zach Davies, Wily Peralta and Jimmy Nelson.
Garza, who went 1-1 with an 8.59 ERA in six spring training starts, was emotional while talking about his injury after the Brewers returned to Miller Park on Thursday from their complex in Phoenix.
Fighting back tears, a disappointed Garza said the groin felt tight after his last start Sunday against Oakland. He allowed five runs and five hits in 2 1/3 innings.
"I just keep thinking about the `Rocky' movies," said Garza, referring to the iconic boxing movies starring Sylvester Stallone. "I can either be the middle fight, or I can be the last one. ... I want to walk out there and fight the championship rounds. It sucks right now. I have to keep on fighting."
Manager Craig Counsell said he doesn't think Garza has a serious injury. The team hopes he will be able to go on a rehab assignment in April.
Anderson was 0-1 with a 3.77 ERA in five spring games, including three starts. He will start Friday's exhibition game at Miller Park against the Chicago White Sox, and then will slot into the fourth spot in the rotation between Peralta and Nelson.
Another job in the bullpen has been filled after Counsell said left-hander Tommy Milone had made the team as a reliever. Milone was also competing for a spot in the starting rotation, while Garza's injury opened up a job for Anderson.
"We waited and waited and then this happened," Counsell said. "That kind of made the last decision."
More AP baseball: https://apnews.com/tag/MLBbaseball