The injury happened in Florida's 7-6 win in 12 innings over the Orioles at Land Shark Stadium on Tuesday.
For a few days, Nunez's ankle has been bothering him.
"It's his ankle, and he had it taped today," manager Fredi Gonzalez said. "We think the tape might have had something to do with it. He had it taped at 5 p.m. [ET], and he had it on at 9 p.m., maybe that had something to do with it.
"We'll evaluate him tomorrow. I don't expect anything crazy about him. We'll see tomorrow. If he's OK, then he will be available."
Florida's primary setup right-hander, Nunez faced two batters and both scored. Matt Wieters opened with a home run, and Robert Andino singled. Immediately, trainer Sean Cunningham and Gonzalez came to the mound, and Dan Meyer entered in relief.
Nunez has appeared in 37 games, and has been the bridge reliever to closer Matt Lindstrom.
Joe Frisaro is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.