Sosa was ejected in the first inning after his bat shattered on a groundout to second base and pieces of cork were found among the shards. Plate umpire Tim McClelland conferred with his crew, then ejected Sosa for using a corked bat. Sosa apologized "from the bottom of my heart" after the game.
He acknowledged ownership of the bat, explaining that he occasionally used it for batting practice and for home run exhibitions to entertain his fans. He said it had been inadvertently mixed in with his regular bats.
"I just picked the wrong bat," he said. "I apologize to my team, to my fans. I apologize to the commissioner of baseball."
McClelland said he saw a half-dollar-sized piece of cork in the bat, about halfway down the barrel.
"I didn't want to do it," he said of his decision to eject the popular Sosa, "but obviously the evidence was right there. You've got to go by the rules."
Sosa said a representative from Major League Baseball confiscated all his bats but insisted no other corked ones would be found.
"This is something I take blame for I feel really bad," Sosa said. "I don't need to use this. I'm a really strong guy. And I'm a fighter."
His teammates were standing behind him after listening to his postgame explanation.
"He came up and faced the music," Kerry Wood said. "He faced the press and dealt with it. The guy made an honest mistake, and he's sorry."
"He feels like he let everybody down," Harris said.
Cubs manager Dusty Baker conferred with McClelland but didn't argue the ejection. He said he hadn't had a chance to talk with Sosa "because I had a game to manage," but he seemed taken aback by the turn of events.
"I believe Sammy didn't know it was in there," Baker said. "My reaction is to wait to see what the league office does. I believe Sammy didn't know it was in there."
Punishment for previous corked-bat incidents have ranged from seven- to 10-game suspensions.
"That's what's so bad," Harris said. "Pretty much we lost our best player. We need him."
The Cubs had runners on second and third with one out when Sosa shattered his bat on a grounder to second baseman Marlon Anderson. Mark Grudzielanek scored on the play, but McClelland ordered him back to third after ejecting Sosa for use of an illegal bat.
Sosa had been 2-for-15 with one RBI and eight strikeouts since returning from the disabled list, where he had spent nearly three weeks after surgery to remove the nail on his right big toe.
Troy O'Leary led off the Cubs' ninth with a single to center, moved to second on Moises Alou's single to left and advanced to third on Hee Seop Choi's sacrifice bunt. With Ramon Martinez at the plate, Levine uncorked a wild pitch, allowing O'Leary to score the winning run.
Mark Prior yielded two runs and struck out five over eight innings for the Cubs. Former Cub Jeremi Gonzalez allowed just one earned run through six innings for the Devil Rays. Mike Remlinger (4-0) picked up the victory.