Tom Gorzelanny will return to the starting rotation.
"[Zambrano's stay in the bullpen] is not short term, that's for sure," Cubs manager Lou Piniella said before Saturday's game against the Chicago White Sox. "We don't know how long [the suspension] will be. I guess it will be cleared up the following week."
After surrendering four runs to the Sox in the first inning Friday, Zambrano began screaming in the dugout and knocked over a Gatorade cooler. He then started yelling at teammate Derrek Lee before Piniella intervened and sent Zambrano home.
General manager Jim Hendry suspended Zambrano indefinitely. Assistant general manager Randy Bush said the Cubs sent a letter to the league on Friday and were awaiting feedback on how to proceed.
"It's impossible for a team to function with the things that were said," said Piniella, who was asked if Zambrano would have been treated differently had he been winning this season. "Winning and losing are important, but they're not that important. Things that were said were not apropos.
"The losing has been tough on me, but something like this shouldn't happen. There's really no excuse for it. These guys are trying, I know we're struggling, but we're trying, believe me."
After struggling as a starter early in the season, Zambrano was sent to the bullpen. But after a mostly ineffective stint as a reliever, Zambrano returned to the rotation and went 2-2 before his start Friday.
It doesn't help that Zambrano is just 3-6 with a 5.66 ERA and hasn't pitched to the form that led to the big contract, but the Cubs insisted there's no connection between his performance and his punishment. Piniella also said Zambrano owes the team an apology.
"Is it a relationship that can be repaired with the team? I definitely believe so," Ted Lilly said.
Alfonso Soriano said he planned to call Zambrano to "see how he's doing." A year ago, Soriano had strong words for Milton Bradley after he got sent home by Piniella following an outburst in the dugout at U.S. Cellular Field, but he called this "a totally different situation."
"When Milton did it, he'd been doing it the whole year -- getting upset for nothing," Soriano said.
The Cubs called a team meeting to address the Zambrano situation and other topics before Saturday's game.
"It's a time I felt we needed to talk about some things," Piniella said. "We had a very open discussion where players got involved. I'm not going to divulge what we talked about, but one of the things we did was the fallout from yesterday.
"We needed a meeting today to clear some things up."
Information from the Associated Press was used in this report.