He can't be serious ... can he?

CHICAGO -- Of all the idiotic things Carlos Zambrano has done in his career, walking out on the nearly $24 million remaining on his contract would definitely top them all.

But no one, not even the Cubs' embarrassment of a pitcher, is foolish enough to do that. Or is he?

According to Cubs manager Mike Quade, who clearly did nothing to cover up for his irrational right-hander, Zambrano told team personnel he was retiring after giving up five home runs and then being ejected for throwing a little too close to Chipper Jones in Friday night's game against the Atlanta Braves.

"I'm really disappointed," Quade said. "His locker is empty. I don't know where he's at. He walked out on 24 guys that are battling their [butts] off for him. I don't know where he's gone or what he's doing. I heard he's retired, or talking about retiring."

Lord knows we've been down this road before. Well, maybe not this exact road, but the same avenue of the inane, on which Zambrano does something stupid, threats are made, apologies follow and the only thing for certain is his stock continuing to plummet.

If it was any lower, they'd be talking about him on CNBC instead of ESPN.

If Zambrano really does quit, the Cubs no longer will be on the hook for the $24 million owed to him for the remainder of this season and the entire 2012 campaign. If Zambrano isn't thinking rationally enough to avoid that scenario, surely his agent would be able to explain in simple terms why another lame apology would make more sense. (Technically, there likely would be some sort of buyout negotiated, but it's fair to assume Zambrano would be getting much less than he would if he were to play the final season of his deal.)

Quade, who wishes his only problem was Zambrano, likened the pitcher's hasty exit to an act of treason. In baseball, this is much worse than giving up five home runs.

"Whatever your thoughts are after a tough outing, you don't leave your teammates," Quade said. "To hell with me. You don't leave your teammates.''

It just all seems so tired. Even as he went 2-0 through the first two weeks of August, Zambrano had long since walked out on his team.

He did it when he lashed out at Carlos Marmol and said his club stunk in early June.

"Embarrassing -- that's the word for this team," Big Z said in an all-star display of hypocrisy.

He did it when he had a public shouting match with Derrek Lee last season. He did it with missed flights and fights with the Gatorade dispenser and on and on.

Again, if Friday's was an isolated or even semi-isolated case, you could shake it off. If it were anyone else on the team, it would blow over. But that's the thing. Anyone else on the team doesn't give up five home runs, throw at one of the guys who hit one, walk off the field with a smile, then walk out of the ballpark saying he's quitting.

His antics are as mind-numbing as they are annoying. And at least his clear-thinking teammates have to be feeling the same way. Apparently Zambrano's nameplate was also missing from the clubhouse late Friday night, which evokes any number of entertaining images from Zambrano taking it himself as a souvenir to one of his teammates ripping it off and tossing it in the trash.

But what does this latest idiocy even mean?

Zambrano's no-trade clause is as familiar to Cubs fans as what he's making this season for winning nine games and being a petulant child -- nearly $18 million.

Assuming Zambrano finally waives the no-trade, the Cubs could not possibly be lucky enough to have another team actually want him, much less wake up Saturday morning to find out he really is retiring.

Then again, maybe he's just crazy enough to do it.

A team can dream, can't it?

Melissa Isaacson is a columnist for ESPNChicago.com.