Red Sox shortstop Xander Bogaerts left Sunday's game against Tampa Bay in the seventh inning after injuring his left ankle while sliding into the Rays' dugout.
Bogaerts was covering third base and chasing his own mishandling of a ball relayed by J.D. Martinez when he got hurt.
He needed help to get off the field and walked with a noticeable limp. He was replaced by Brock Holt.
Manager Alex Cora said he expected to know more about the severity of the injury on Monday.
"Further evaluation tomorrow,'' Cora said. "We'll know tomorrow after all the tests and everything.''
Bogaerts went 1 for 3 as Boston beat Tampa Bay 8-7 for its eighth straight win. He is hitting .368 (14 of 38) this season with two homers and nine RBIs.
Holt said he's prepared to step in at shortstop if Bogaerts has to miss any time.
"I feel comfortable at shortstop, second base, third base _ pretty much anywhere,'' Holt said. "It's a tough team to crack the lineup. I hate to see (Bogaerts) get injured there, especially with his spot coming up there (in the eighth inning) in a big spot. But I feel like I can step in and do a good job.''
Boston opens a three-game series against the New York Yankees on Tuesday night.