CHICAGO -- Cubs pitcher Carlos Zambrano has a minor strain of his pitching shoulder, an encouraging result from Friday's medical test, but is still likely to miss his next start Tuesday.

"The good news is there was no structural damage to the two main parts of his shoulder," Cubs general manager Jim Hendry said following Zambrano's MR arthrogram. "The two worrisome parts of his shoulder are the labrum and the rotator cuff, and they're in very, very good shape for a man who has pitched as many innings in the big leagues that he has."

Trainers and coaches will meet with Zambrano on Saturday to determine the next course of action. Sean Marshall could replace the ace on Tuesday against Baltimore, or Sean Gallagher could start.

Zambrano exited Wednesday's game against Tampa Bay after 6 2/3 innings and 101 pitches because of shoulder discomfort. He leads the staff in innings pitched (106 1/3) and is tied with Ryan Dempster with eight wins. Luckily, the Cubs won't be without their workhorse for an extended period.

"He's the guy that we lean on," Ted Lilly said. "Not just what he does on the mound, but he's a presence on our team, in our clubhouse and certainly on the mound. He wants to be out there and answer the call every time so bad, I hope that he's healthy enough to do it. With a guy like him, you really don't want to take any chances [with injuries] because he's the type of guy that, if you give him a chance, he wants to be out there so bad. He's going to have to really, really be hurting seriously not to go out there."

Left fielder Alfonso Soriano, out with a broken bone in his left hand, had an X-ray on Friday that also brought good news. The bone is healing well, and the six-week timetable remains in place for his return. Soriano told the Chicago Sun-Times he hopes to take batting practice on Monday, which would be 12 days after he got plunked.

Cubs manager Lou Piniella wasn't as optimistic.

"Maybe [batting practice] with a Wiffle ball," Piniella joked. "He heals quick, but not that quick."

Outfielders Reed Johnson and Jim Edmonds were available to pinch-hit Friday. Edmonds is getting over turf-induced plantar fasciitis in his left foot. Johnson felt back spasms on Tuesday and did not play for the rest of the Tampa Bay series. He underwent surgery for a herniated disc last year, so the team is playing it safe.

"I'm progressing and feeling better, which is always good," Johnson said. "I've still got some time to heal up. I know if this was in September and playoff time, it would be a situation where I think I would strap it on and get out there. I think we're just being careful with the history that I've had."

The last injury note comes out of Arizona, where Daryle Ward has begun taking batting practice at the Cubs' Spring Training facility. Ward, who is coming back from a bulging disc in his back, could rehab at Triple-A Iowa beginning this weekend. If all goes well, Ward could be the designated hitter for next weekend's series with the White Sox at U.S. Cellular Field.