Cardinals general manager John Mozeliak made the announcement on Saturday before a short workout. Garcia underwent season-ending surgery last year after experiencing shoulder pain.
Garcia's throwing sessions at spring training had been going well until his last outing, when the pain returned.
''He just hadn't quite felt right for the last 48 hours,'' Mozeliak said. ''From a medical standpoint, no one thought it was that serious. But it wasn't improving and given how early it is in camp, there's no reason to try to work through something if it might be something larger. We think it is better to get some resolution and have him seen back in St. Louis.''
The 27-year-old Garcia had been the favorite to become the fifth starter, and lone lefthander, in the rotation. He was 5-2 with a 3.58 ERA last season and won a career-high 13 games in 2010 and 2011.
Mozeliak didn't want to speculate on the severity of Garcia's injury, but said it's ''probably unlikely'' he'll be ready for opening day. He added that some soreness following shoulder surgery is not uncommon.
''Any time a pitcher that has thrown as much as he has experiences shoulder pain, goes in and gets a cleanup, it's not too hard to imagine that there could be still an uphill battle,'' Mozeliak said.
Garcia had been scheduled to throw a bullpen session on Saturday, but the soreness canceled those plans. Mozeliak said he expects to know more about Garcia's status on Monday.
''I don't think it's any secret to anybody that having that solid lefthander seems to add a different component to an offense that might be locked in against some righties,'' Cardinals manager Mike Matheny said.