Garcia's absence until then leaves the Cardinals needing a spot-starter for Thursday's series opener against the Padres. Matheny announced after Wednesday's 7-1 loss to the White Sox that the Cardinals will bring up lefty Tim Cooney from Triple-A Memphis.
Cooney, who made one spot-start for the club in April, was pulled from his outing with Memphis on Sunday after throwing just 26 pitches. Afterward, general manager John Mozeliak confirmed that the organization pulled Cooney in order to keep him available as an option in St. Louis later in the week.
As for Garcia, he once again spent time throwing on flat ground on Wednesday afternoon. He expects to throw a bullpen session sometime over the next few days and then put himself through running tests.
"I'm very encouraged by how I feel today and how I've felt the last couple of days," Garcia said. "I'm very confident that [my next start] will be as soon as Chicago. Things are progressing really well. It was more of a precautious move not pitching [on Thursday]. Just give it a couple days of backing off, and I should be good to go."
If the Cards had placed Garcia on the DL, he would not have been eligible to return until July 10, which would have meant another missed turn in the rotation.
"I don't want to go on the DL ever again in my career," said Garcia, who opened the year sidelined by a shoulder injury. "I want to be out there every single start, and that's my goal, to make every start the rest of the year. I'm doing everything in my control to make that happen."
The Cardinals' other rotation option would have been to bring Michael Wacha (Thursday) and Carlos Martinez (Friday) back on regular rest and try to slot Garcia back in on Saturday. That was not the preferred course, however, since it would have eliminated an extra day of rest for Wacha and Martinez, both of whom are having their workloads closely monitored.
"We talk all season about having those potential days where we can get young guys a little bit more rest, and this is one of those examples," Matheny said. "We could have kept them on regular [rest] and they would have been fine. But give them that extra day will help us out in the long run."
Jenifer Langosch is a reporter for MLB.com. Read her blog, By Gosh, It's Langosch, follow her on Twitter @LangoschMLB and like her Facebook page Jenifer Langosch for Cardinals.com. This story was not subject to the approval of Major League Baseball or its clubs.