Garza was scratched from his scheduled start at Boston on Sunday night and eventually diagnosed with an elbow bone contusion. The DL stint is retroactive to May 18, and he could return when Chicago travels to St. Louis for a weekend series on June 3-5.
"I'm not happy to be on the DL," Garza said. "I fought it. It's not like I chose to do it. The team and everybody above me feel it's the best thing to do and I trust their advice. There's nothing I can do. I'd rather be out there 100 percent than put myself in jeopardy and put the team in even bigger jeopardy."
The 6-foot-4 right-hander is 2-4 with a 3.72 ERA in nine starts in his first year with Chicago. He won 15 games with Tampa Bay last season and was acquired in a trade over the winter.
"It's just a deep bone bruise with some inflammation around the joint," general manager Jim Hendry said. "The good news is he knows it's not going to do any damage to the ligament, which is always the most important thing about getting MRIs. It's the best news we could have hoped for and there is improvement since Boston already."
Garza joins Randy Wells and Andrew Cashner among the starting pitchers on the injured list. Wells (strain in his right forearm) is expected to come off the DL to start Saturday against Pittsburgh. Cashner (rotator cuff strain) visited Dr. Lewis Yocum in California on Tuesday, and the renowned orthopedist confirmed the righty doesn't need surgery.
"It is what it is," Garza said of the banged-up rotation. "You can't really control that. As long as you have guys who can go up there and run it up and carry the staff while other guys are down. When we get back to full strength, it's gonna be fun to get after it."
Outfielder Lou Montanez was promoted from Triple-A Iowa to take Garza's roster spot and started Tuesday night against the New York Mets. He had an RBI double in the second inning.
To make room for Montanez on the 40-man roster, right-hander Brian Schlitter was transferred to the 60-day disabled list.
AP freelance writer Travis Miller contributed to this report.
Jay Cohen can be reached at http://twitter.com/jcohenap