Whether Matt Garza will start the season in the rotation is now in question because of his left lat strain.

"We're not going to rush this guy, that's for sure," general manager Jed Hoyer said.

Garza will have an MRI to determine the extent of the injury, which he suffered Sunday during his first live batting practice session.

Garza, who was sidelined the final two months last season with elbow soreness, will fall behind in his rehab.

"The good news is his arm felt really strong," Hoyer said. "It's unfortunate for sure and it's going to set him back a little bit. But we're still really confident. Our concern obviously was with the elbow injury that shut him down last year."

Manager Dale Sveum said Garza still was sore Monday, "but there was no discoloring" around the injured area. It's too early to know, but Garza could be on the disabled list opening day. The Cubs have to determine how much rest he'll need before starting again. Ryan Dempster suffered a mild lat strain last June and went on the 15-day disabled list.