Gaudin was examined Monday by Dr. Michael Shafer in Chicago. Gaudin's back is still sensitive, and he was sent to the Cubs' facility in Mesa, Ariz.
"He says he gets a tingling down in his buttocks when he throws the ball," Cubs manager Lou Piniella said Tuesday. "His absence has hurt us. He's a guy we counted on in the middle of the ballgame when we took our starter out, and it's created a void for us."
The Cubs' bullpen has been shorthanded with Sean Marshall moving to the rotation to fill in for Carlos Zambrano. On Tuesday, Zambrano had a good throwing session, and he is on schedule to start Saturday against Houston. Rich Harden threw on the side Monday and will start Thursday in the series finale against the Cardinals.
"I think if we get our two starting pitchers back into the rotation, I think it will help stabilize things," Piniella said.
Of course, whether Zambrano starts and the Cubs even play the Astros may be up to Mother Nature. Hurricane Ike was headed for Texas, and Piniella said he expects to know more Wednesday about alternate plans.
"We're pretty sure Zambrano will go Saturday in Houston, unless Hurricane Ike takes a course down through the Gulf of Mexico like I took to Cincinnati from Chicago," Piniella said, referring to his misdirected trip on Friday.
The Cubs did get shortstop Ryan Theriot back in the lineup Tuesday. He had to come out of Sunday's game against Cincinnati after feeling dizzy. Theriot was dehydrated, and he was a late add to the starting lineup in the series opener against the Cardinals. He was examined by a doctor in St. Louis.
"The doctor assured him that everything was fine," Piniella said.
The Cubs manager was asked if he was worried heading into the final 19 games.
"The amazing thing about managing a baseball team is if you're a little bit of a worry wart, you worry every single day," Piniella said. "Halfway through the year, you need a psychiatrist, and by the end of the year, you need a bed."
Carrie Muskat is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.