Zambrano's agent Sunday said the players association will file a grievance Monday over the Cubs placing the 30-year-old right-hander on the disqualified list Saturday.
The club took the action one day after Zambrano left Turner Field after being ejected from his start against the Atlanta Braves, taking his equipment with him and apparently telling people he was retiring from baseball.
The retirement talk now is said to be premature, but it remains questionable, if not highly doubtful, that Zambrano ever will pitch for the Cubs again.
General manager Jim Hendry called Zambrano's actions intolerable and went so far as to apologize to the Braves for Zambrano throwing two pitches at Chipper Jones, prompting the ejection.
"This is the most stringent penalty that our club could inflict without a release," Hendry said in explaining the move to the disqualified list.
Zambrano spent a month on the restricted list last year after a dugout tirade during a game against the White Sox in June. He underwent anger-management treatment and proclaimed himself "cured" during spring training. Earlier this season, Zambrano said the team "stinks" after teammate Carlos Marmol blew a save.
Teammates apparently are just as tired of Zambrano's act as is the organization. Saying they were relaxed, the Cubs won two of three from the Braves, including Sunday's 6-5 come-from-behind victory.
"He's has been doing a lot of things, not once or twice," said left fielder Alfonso Soriano.
"I think he made his stance pretty clear of what he wanted to do," said pitcher Ryan Dempster, referring to Zambrano's initial talk of retirement. "The guys in here are pretty upbeat. He made his bed. He has to sleep in it."
If the stint on the disqualified list holds, Zambrano will not be paid for 30 days, during which time he may not have any contact with the team.