Cubs' rotation in state of flux

MIAMI -- When it comes to the Cubs' pitching rotation, nothing is set in stone, including Thursday's start by Steve Trachsel.

If the Cubs can clinch the National League Central against the Marlins, manager Lou Piniella likely will reshuffle his deck to set playoff matchups. Even if the Cubs don't clinch here, he may change things. The only thing certain is that Jason Marquis will start tonight.

"If we knew we're in the playoffs, we could do a lot of adjustments," Piniella said. "And we'll probably tinker with our pitching here between now and Sunday, too.

"The way we're scheduled, I wouldn't go to the bank, exactly, with it, either. I think probably regardless (whether the Cubs clinch). We'll see what happens with this thing.

"We're looking at it from a lot of different angles. We'll see what happens today or tomorrow."

The Cubs could go with Carlos Zambrano, Rich Hill and Ted Lilly this weekend in Cincinnati. That would set Zambrano up to pitch Game 1 of the National League division series next Wednesday, if the Cubs make it.

Now, it appears all bets are off. As for tonight, Marquis said he's ready, especially after going only 2¿ innings last Friday.

"Obviously, you learn from what mistakes were made, and that's what you take out of it," he said. "You don't sit there and dwell on it. It's a long season. You're not going to go out there and dominate and deal every time."

Ronnie's back: Radio analyst Ron Santo returned to the WGN radio booth after missing the weekend because of illness. Santo said he was felled by a virus and congestion in his chest.

Santo, who has made several comebacks from diabetes-related illnesses, missed the 2003 playoffs because of bladder cancer. He wasn't about to miss this final push to a possible playoff spot.

"This is why I stayed home," he said. "Each day I got up and got dressed. I started the car. My wife was standing there, and she said, 'You're not going to make it.' She said, 'You're on a quarter of a tank (health wise), and you want to go on the trip. Just stay home.' "

Theriot, too: Shortstop Ryan Theriot was back in the starting lineup after missing Sunday's game because of lower-back spasms.

"I wanted to be on the side of caution," Theriot said. "It did lock up a little bit. Luckily, we have somebody extremely capable to go in there and fill in (Ronny Cedeno). But, no, I feel fine."

Theriot said the injury happened in Saturday's game but he played through it.

"Just a little tweak when I hit first base and kind of got progressively more stiff," he said. "The following day, I took it easy in b.p. (batting practice), but quite honestly, I could have played. I've played with it worse this year, honestly."

This and that: Both Lou Piniella and team president John McDonough laughed off reports that the New York Yankees' Alex Rodriguez would sign with the Cubs this winter and get an ownership stake. That would be against baseball rules. … Pitcher Carlos Zambrano, who cramped up from dehydration Sunday, threw in the outfield Tuesday. The Cubs said he's fine. … Geovany Soto started his fifth straight game at catcher. Lou Piniella said the rest would be good for veteran Jason Kendall, whose thumb is "beat up," according to Piniella.