In the second, the White Sox had two runners on and Joe Crede tried to check his swing on a pitch from Cubs starter Sean Marshall. Crede appeared to go around, but first-base umpire Chad Fairchild said Crede held up, and called a ball.
Piniella argued with Fairchild, and as he headed back to the dugout, home-plate umpire Rob Drake signaled that the Cubs skipper had been tossed. Piniella had his back to Drake when he made the call.
Piniella then went over to argue with Drake, and third-base umpire Jeff Kellogg had to step in between the two.
Piniella was ejected once last season, his first with the Cubs, on June 2, and the team seemed inspired after that. The Cubs have gone 112-79 since June 3, 2007, second best in the Major Leagues to the New York Yankees. The Cubs lost, 5-1, to the White Sox on Sunday, and have dropped four in a row, their longest losing streak of the year.
"Lou wasn't talking to the home-plate umpire when he got thrown out of the game," Cubs catcher Henry Blanco said. "I don't know what they have in their mind, I don't know if they want to argue, they don't want to argue. I don't think there was any reason for him to get thrown out of the game."
Bench coach Alan Trammell said you can't argue a checked swing.
"You might be able to ask a question," Trammell said. "I think Lou was frustrated. We disagree, and we'll see a replay and we're wrong. I'm not saying that's the case this time, but that's what happens in the heat of the battle."
After the game, Trammell subbed for Piniella in the media interview room. Piniella was unavailable for comment.
Carrie Muskat is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.