Chicago Cubs right-hander Matt Garza suffered a mild back strain on his left side while throwing batting practice to teammates Sunday and is expected to miss at least a few days of practice.

Whether it will delay his start to the regular season, team officials said they would know more about his prognosis after he is examined again Monday.

"It looks like a mild lat strain," manager Dale Sveum said. "We'll see what happens when he wakes up and see where we are a little bit more [Monday]. But it's subsided, and he seems to be doing a lot better now."

Garza got halfway through his throwing schedule when he felt a twinge and left the field with the trainer.

"The ball felt good coming out of my hand. I think that's what I'm most upset about," said Garza, who was considered a candidate to be the Cubs' opening day starter. "But it shouldn't be a big thing, and we'll see [Monday]."

Garza hasn't pitched in a game since July 21, when he left a start in St. Louis because of a "stress reaction" in his pitching elbow.

He has looked impressive the first week of spring training.

"Hopefully, it's really nothing and he doesn't even get really set back as far as opening day, and if not, then we'll have to obviously evaluate the [timetable]," Sveum said. "We have the depth. It's not that big a deal that way. It's just too early to know what plan we're going to take."

With six weeks left before the season opens, Garza said he doesn't think he'll miss any time.

"They tell me good things, and I look forward to [Monday] and see what's going on."