With one out in the Cubs' first inning and runners at first and third, Ramirez hit into a double play. But he couldn't make it to first base, grabbing his left thigh as he ran down the line and stumbling a few steps before reaching the bag. Ramirez fell and lay on the dirt. He was able to walk off the field gingerly with help from Cubs athletic trainer Mark O'Neal.
"We didn't feel a significant defect in the quad itself," O'Neal said of results from an early exam. "Obviously, you're looking to make sure you don't have any major muscle disruption like Nomar [Garciaparra] had [with his groin], and we didn't find anything like that."
O'Neal did not want to estimate how long Ramirez would be sidelined until seeing the test results and re-examining the third baseman after Thursday's off-day.
Ramirez had problems with his left quad last year, and has been bothered by a sore right quad since late July this season. He was batting .275 this month and .303 overall, and leads the Cubs with 92 RBIs.
"It's another hit," Cubs second baseman Todd Walker said of losing Ramirez. "I guess at this point you could say it's almost expected that somebody you depend on is going to go down. I've never heard of this, much less seen that many people you depend on go down."
So far this season, Garciaparra, Walker, Kerry Wood, Mark Prior, Scott Williamson, Jerry Hairston, Chad Fox and recently departed Mike Remlinger are among the Cubs who have gone on the disabled list.
"It's been freakish, all the injuries, especially to key guys," Cubs first baseman Derrek Lee said. "It's something you have to deal with and can't use as an excuse."
Infielder Ronny Cedeno, who had been playing with Triple-A Iowa, was in Chicago on Wednesday in case Garciaparra had to go on the disabled list. No roster move was made, but Cedeno may be needed if Ramirez is to be sidelined for an extended period.