ST. LOUIS -- Chicago Cubs pitcher Kerry Wood will not start on Sunday but be pushed back to Tuesday because of stiffness in his right shoulder.

Greg Maddux (6-4, 4.32 ERA), who was to start Monday in the series opener against Houston, will now pitch on Sunday for the Cubs against the St. Louis Cardinals. Carlos Zambrano (3-3, 3.42 ERA) will start Monday. Both Maddux and Zambrano will be on normal rest.

"[My shoulder] didn't recover the way I would've liked it to," Wood said Saturday. "I bumped the intensity up a little bit the last start, and I didn't recover as good as I have been. This way, I'm not [messing up] anybody. We keep Maddux and Zambrano on their fifth day. I'll keep getting treatment and be ready to go on Tuesday."

Wood (1-1, 4.50 ERA) is coming back from arthroscopic surgery on his right shoulder in late August. He made his first start on May 18, and was able to go May 23 on normal rest. Wood was given an extra day before his last outing on May 29.

The switch is no cause for concern, Cubs manager Dusty Baker said.

"Sometimes it's going to happen and you're not going to rebound the same way every time, especially when you just come off what he came off of," Baker said. "We think he'll be fine. We'll take some precautions and keep the other two guys on schedule."

The Cubs had an off-day Thursday, which is how the other pitchers stayed on schedule. Wood has said he'll take advantage of an extra day when possible.

"Hopefully we're playing for something here," Wood said. "Maybe we can take our days now and get ready to roll in the second half. It comes with the shoulder surgery. There's good days and bad days. Take advantage of the extra days here, keep other guys on their five-day rotation and keep going."

Wood has had both elbow and shoulder surgeries, and is learning every day the difference in the two.

"Before my last start and during my last start is the best I've felt since getting off surgery," he said. "You recover as well as you can. You listen to it and pay attention to it."