Bob Watson, Major League Baseball vice president of on-field operations, issued the ruling after receiving a report from the umpires and talking to Cubs general manager Jim Hendry.
"When you make a mistake, when you do something wrong, I don't have a problem with that," Zambrano said of the suspension. "I disrespected [Major League Baseball], and I apologized, like I did yesterday, and let's move on. I accept the suspension."
The Cubs led, 2-1, in the seventh inning Wednesday when Nyjer Morgan tried to score on a wild pitch. Catcher Geovany Soto flipped the ball to Zambrano, who was covering at the plate, but Morgan slid and appeared to sneak his left hand in. Home-plate umpire Mark Carlson called Morgan safe, but Zambrano disagreed. The pitcher and umpire went nose to nose, and they briefly bumped.
Carlson tossed Zambrano, who mimicked the heave ho, signaling that he thought the umpire should be ejected.
Cubs manager Lou Piniella and pitching coach Larry Rothschild ran onto the field, but it was too late. Zambrano hurled the baseball into left-center field and then threw his glove as he stalked off the field. He also took a bat to the Gatorade dispenser in the dugout.
"I don't have any problem with the call either way," Hendry said. "In fairness to [Zambrano], when you look at the tape, when he made the tag on the right hand, looking down in front of him, I can see how he felt [Morgan] was out. The left hand was underneath his leg and not in full view for him."
Zambrano met with Piniella and Rothschild on Thursday.
"We told him basically that we weren't happy about the situation and we're not going to condone it," Piniella said. "There's nothing wrong with being upset, but you have to learn to walk away at the right time.
"I think it's behind him," Piniella said. "He feels bad after it happened, which is really the right approach. You've got to learn to take it to a certain level and walk away from it. There's nothing wrong with disagreeing at times. Look, when you get to a certain point, certain level, you get back on the mound and you pitch and concentrate on getting people out and winning baseball games."
Zambrano said he appreciated Piniella's concern.
"[Piniella] said some things, and we got everything cleared up," Zambrano said. "Any time you get called to the office, it's because they're worried about you and they're trying to tell you something."
Zambrano was asked if he needed to change his behavior, but the pitcher has never argued with an umpire like this in the past. A radio reporter mentioned there had been other incidents and brought up the fight two years ago between Zambrano and Michael Barrett in the Cubs' dugout.
"How can you bring Michael Barrett into the conversation?" Zambrano said, his voice rising. "I'm a man. Somebody comes to me and tries to beat me up, I have to respond. Nobody likes to get beat up. I didn't say this to the umpire. But if some man here or some man outside tries to get me, or fight me, I will respond. Any man here would respond. Am I right?
"Don't bring Michael Barrett into this conversation," Zambrano said. "We're talking about the incident yesterday, not Michael Barrett."
The subject was quickly changed. The Wrigley Field crowd definitely enjoyed watching Zambrano go ballistic. He didn't.
"I'm disappointed," Zambrano said. "The fans enjoyed it, but I'm disappointed in what I did yesterday. Let's move on."
"He's a wonderful young man, and I love the guy to death," Piniella said. "I enjoy kidding around with him in Spanish all the time. I'll tell you what, he's got a quick fuse. He told me this hasn't happened in a long time. I said, 'Let's hope it doesn't happen ever again.'"
Zambrano's fans will be disappointed to hear that.
"Well, this is not [World Wrestling Entertainment]," Piniella said. "This is professional baseball. I understand the fans like a little -- I don't know what you call it -- emotion, outburst. They've always liked that, especially about the seventh inning, when they've had [a few beverages].
"Baseball has always been a sport where there's been disagreements," Piniella said. "But at the same time, you voice your disagreement and walk away from it and you get back to do what you're getting paid to do, which is pitch or hit or whatever it is."