MESA, Ariz. -- After an MRI revealed a "mild strain" in his lower left lat area, the team said Tuesday that Cubs right-hander Matt Garza will be shut down for at least a week, which could put his status for the start of the regular season in doubt.

Cubs general manager Jed Hoyer described the news as "positive."

``It's safe to say it pushes back his first Cactus League start,'' he said. ``What it means for the regular season it's clearly much too early to say, but we felt like it was really good news. It is a mild strain. We do think it'll be about a week and he'll be pain-free, based on the MRI.

``We're optimistic. It was certainly a positive read from out standpoint.''

Garza, who spent the last two months of the 2012 season on the disabled list because of a "stress reaction" in his elbow, suffered the latest injury - where the lat meets the oblique on the left side - while throwing batting practice to teammates Sunday.