Rodriguez has been battling tightness in his right groin since last weekend in Toronto, a situation he attributed to the artificial turf at Rogers Centre. Extra stretching has helped him get loose since then, but a series of cramps on Thursday made that impossible.
The three-time American League MVP played the first inning on Thursday but froze when Adam Jones rolled a ground ball to his left. Rodriguez was replaced by Ramiro Pena when the Yankees came to bat in the second inning.
"Not only did I not make a play, it was a routine play. It's a play you make 10 out of 10 times. I just locked up," Rodriguez said. "At that point I pointed to [Pena]. I had warned him about 15 minutes before the game to make sure he was ready."
Manager Joe Girardi noticed Rodriguez performing extra stretching exercises before batting practice but was assured by Rodriguez that he had loosened up. Rodriguez said that "10 or 12 minutes" before first pitch, the cramps started again.
"I think we've all felt it at some point," Rodriguez said. "Sometimes you wake up and you get a cramp in your calf or your hammy or whatnot. It's frustrating because there's no pain. But these cramps, we've got to figure them out."
Rodriguez will be examined by Dr. Christopher Ahmad in New York, with an MRI a possibility. He also mentioned that he might lean on Dr. Marc Philippon, the Vail, Colo.-based specialist who performed his hip surgery, for further advice.
"The fact that he doesn't have pain makes me feel a lot better," Girardi said, "but that doesn't mean that you're completely out of the woods."
Rodriguez said there was "nothing in particular" he did during batting practice that should have aggravated the injury.
"I took my ground balls, and right before BP I just felt kind of like a cramp," he said. "It's hard for me to describe. I've never felt that way before."
Girardi would not second-guess his decision to play Rodriguez on Thursday, because Rodriguez had been able to get loose for the game on Tuesday and Wednesday.
"At times you're going to be stiff and you're going to go out there. Players do that all the time," he said. "In hindsight, maybe you would have rather [not started Rodriguez], but he felt that he could go, and it just didn't work out."
Bryan Hoch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.