On Friday, Bradley threw his helmet and one of the water coolers after a bad at-bat in the sixth inning, and Piniella decided he'd had enough of the outfielder's tantrums. He told Bradley to take his uniform off and go, but then followed Bradley into the clubhouse, where the two exchanged words.
Bradley was surprised Piniella followed him into the clubhouse.
"He told me to get out of here, so I left," Bradley said. "Then he continued to yell at me some more."
Others on the Cubs have had fits -- Carlos Zambrano took a bat to the Gatorade cooler at Wrigley Field and Ryan Dempster punched it with his left hand. On Friday, Carlos Marmol threw one of the Gatorade coolers, too.
"This has been going on for a while," Piniella said of Bradley's tantrums. "I've talked to the other people, too. The first thing is you don't want people getting hurt. I've talked to a couple other people here rather strongly about it.
"[Friday], I was right in doing what I did. I probably should've just stayed in the dugout. I heard him mumbling some things and I followed him up. I'm sorry it happened and I wish it hadn't. That's all I can say."
Piniella, 65, said he couldn't enjoy the Cubs' 5-4 win over the White Sox on Friday, nor dinner with his wife that night.
"I don't like these sort of things," Piniella said of his confrontation with Bradley. "It really took the joy out of winning a baseball game for me."
What was also bothersome to Piniella and several of the Cubs players was that the manager's comments were leaked.
"We have the sanctity of a clubhouse here," Piniella said. "I'm disappointed that something like that gets out. There are a lot of heated things that are said in the clubhouse at times and they should stay there."
Bradley spoke to a handful of reporters prior to Saturday's game between the Cubs and White Sox.
"The last time somebody [made a similar comment], I tore my ACL," Bradley said, referring to an incident when he was with the Padres and got into an argument with umpire Mike Winters. "I know how to deal with that.
"It's Lou Piniella, you know what I'm saying?" Bradley said. "To me, Lou Piniella is somebody. If it's a motivating tactic and he's taking a different switch -- people were saying he didn't have fire -- then I understand. I heed what he has to say. It matters. I take it to heart. I'll be better for it."
Bradley said a manager has never told him to leave a game. He tried to put the matter behind him.
"My head's fine," Bradley said. "I never had a problem mentally. Sometimes I react bad about things but I'm an extremely intelligent individual. I don't see why my head wouldn't be clear."
Does he feel as if he's being singled out?
"Like I've said, I don't have the same set of rules as other people," Bradley said. "I've made mistakes in my past, so you don't get the leeway that other people might get. Considering the circumstances, I guess it's fair."
The two have apparently made peace.
"I don't have a problem with Lou at all," Bradley said. "It's hard for me to get upset with a teammate. He's the manager, he's more than a teammate. Initially, I was just kind of shocked at how everything just happened suddenly."
Bradley signed a three-year, $30 million contract with the Cubs this past offseason, but has struggled at the plate, and was batting .237. Cubs general manager Jim Hendry talked to Bradley on Friday night, and planned to meet with him before Saturday's game as well. Hendry said he supported Piniella in how he handled the matter.
Now, the Cubs have to get Bradley back on track.
"He's certainly capable of being an outstanding player," Hendry said. "He has been a very successful hitter his whole life. I'm sure the frustration level is at wit's end for him. It doesn't condone certain actions that you don't want a player to do. We're still in a good spot to make a run at things in the second half, and we could use the Milton Bradley bat that we signed up for."
The Cubs had hoped Bradley could be the left-handed hitter missing from the lineup. The team has bent over backwards for him, contacting some of his former hitting coaches for help to get the outfielder on track. Players have tried to help the volatile Bradley, but he hasn't bonded with anyone, and lost a good friend on the team when hitting coach Gerald Perry was dismissed.
If Bradley were performing on the field, he wouldn't be leading the National League in broken helmets. He wouldn't be testing Piniella's patience. But he isn't.
"I think this young man put a lot of pressure on himself," Piniella said. "I think he needs to relax and let his ability flow. I think he'll be much better off that way. Personally, I like Milton. He's a bright kid, he's a good-looking young man. He's trying too hard. Then he's fighting and that just compounds the problem over and over and over again. [Friday], I'd had enough."
Carrie Muskat is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.