CHICAGO -- Cubs outfielder Milton Bradley was pulled from Thursday's game against the Brewers in the sixth inning because of left knee inflammation.

Bradley had told Cubs manager Lou Piniella and athletic trainer Mark O'Neal that his left knee was bothering him before his at-bat in the sixth. The outfielder was hit by a pitch in the first and popped up in the fourth.

"We let him hit, he got a base hit, and we had [Bobby Scales] getting loose to run for him," Piniella said. "That was it."

After Bradley singled, he said something to Cubs first-base coach Matt Sinatro, then headed for the dugout. Scales took over as a pinch-runner.

Bradley did not want to talk about his knee postgame.

"I have knee inflammation," he said. "I've had two knee surgeries. It happens when you have knee surgery, in case you don't know."

It's uncertain whether Bradley will miss Friday's game in St. Louis. Asked if he was day to day, Bradley snapped.

"What else you got? You got anything significant?" he said. "If you have some baseball questions, I can answer. I've got nothing for you."

Scales subbed in right field after Bradley was pulled. The Cubs are short-handed as far as outfielders on the roster, and added 40-year-old So Taguchi on Wednesday. He had played for Triple-A Iowa, and was sitting at home when he got the call. Alfonso Soriano underwent arthroscopic surgery on his left knee Tuesday, Reed Johnson was still sidelined with a fractured left foot and Sam Fuld is out because of a strained right thumb.