Garza took the mound Saturday in St. Louis, but he was taken out after pitching three scoreless innings with cramping in his right triceps, an injury that wasn't obvious and prompted speculation he had been traded.
The Cubs didn't reveal the injury until the bottom of the sixth, adding that X-rays were negative. Justin Germano got unlimited warmups, indicating he was entering the game because of an injury or ejection when he replaced Garza in a 0-0 game.
Despite his early exit, Garza is still with the Cubs, and was plenty frustrated after witnessing a bullpen debacle from the dugout. The Cardinals scored all of their runs in the seventh, tying a major league record with seven doubles in a 12-0 victory Saturday night.
"If that's what they thought," Garza said of the rumors, "It'll take a lot more to pull me out of that game than a trade. They're going to have to wait 'till I'm done."
Garza felt tightness working his third scoreless inning, went straight to the indoor batting cage after the third out to try to loosen up and started cramping. A team trainer told Garza it was "not worth the risk" trying to continue pitching.
"You prep to go and you just can't," Garza said. "I feel like I let my guys down. I know they're going to say I didn't, but that's my job."
Garza, who didn't have the arm wrapped after the game and said it only felt tight, is hopeful of making his next start scheduled for Wednesday night in Pittsburgh.
The Dodgers had a deal on the table for Dempster on Friday, and it appeared the right-hander would have been scratched from his start that night in St. Louis had a trade been consummated. Instead, Dempster gave up three runs in the first inning and allowed four runs in the six innings he pitched in the 4-1 loss.
In order to add Garza, the Dodgers or any other team likely will have to part with more top prospects than they would to get Dempster. Garza is under contract through 2013 and has one more year of salary arbitration left before he can declare free-agent status.
Like Dempster, Garza is not sure who'll he'll be pitching for.
Garza said he was more concerned about his wife being home pregnant and due to deliver a son than changing teams.
"The trade thing, I'm not so concerned about that," Garza said. "I'd rather go out there and throw eight or nine (innings) than come in here and say, 'I can't throw the ball.'
"I've got to get ready for the next one."
Information from The Associated Press was used in this report.