Utley was hit on the tip of the helmet by an Eric O'Flaherty pitch in the sixth inning. Utley left the game for precautionary reasons after complaining of headaches. He likely has a very mild concussion, but was going for testing, according to general manager Ruben Amaro Jr.
"The way to describe it, he didn't feel 100 percent after getting hit," Amaro said. "He felt okay right afterwards, then started feeling a little fuzzy. We took the precaution to get him out of the game."
Amaro said it appeared Utley would be out at least a couple of days and that the second baseman may not go to Milwaukee for a series this weekend against the NL Central-leading Brewers. He wasn't on the team plane Wednesday night.
"When you get a 90-plus mph fastball off the melon, you have to be cautious about it," Amaro said.
The GM also said the Phillies would likely activate shortstop Jimmy Rollins from the disabled list.
"I'll have Charlie use him (Rollins) in emergency purposes," Amaro said.
Rollins has been on the DL since August 22 due to a strained right groin.
In 88 games this season, Utley is hitting .262 with 10 homers and 41 RBI. He went 0-for-2 in Wednesday's game and is mired in a 5-for-40 slump.
Utley began the season on the disabled list with right knee tendinitis and was activated on May 23.
Pinch-hitter Ross Gload singled in the winning run in the ninth inning Wednesday, giving the Phillies a three-game sweep and extending their lead to 10 1/2 games on Atlanta in the National League East.