In May, Cora rehabbed a torn ligament in his right thumb, and he has played without problems since. But after reaching for a throw from right fielder Jeff Francoeur on Tuesday night, Cora had to brace himself, showing some pain.
Manager Jerry Manuel said that Cora would likely only need to take one game off. The team is off on Thursday, which would give Cora two days of rest.
"His last at-bat, I saw him wincing for the first time, and that concerned me a little bit," Manuel said. "He's always said that with that thumb he could hit, but last night it bothered him."
Signed on July 11, Berroa is 0-for-4 as a pinch-hitter with the team. He won American League Rookie of the Year honors in 2003 as a Royal before making stops with the Dodgers last year and the Yankees earlier this season.
Sullivan has not played in a Major League game since August 2008. After hitting .290 for Triple-A Buffalo, he was called up to replace the injured Fernando Nieve -- who tore a muscle in his right thigh on Sunday -- on the roster.
"As far as left field goes, Cory was swinging the bat real well, and Jeremy [Reed] is struggling now, so we're going to see if we can find something there," Manuel said.
After his team was shut out by Washington starter John Lannan on Tuesday, Manuel mentioned in his postgame news conference that he would insert Sullivan into the lineup for a potential spark. Because the left-handed Lannan was on the mound, Fernando Tatis started in left field. He went 0-for-4.
The Mets are in desperate need of some power, as they have hit a Major League-low 53 home runs this year. But that likely is not what Sullivan will bring, as he hit just two for Buffalo this year.
"I'm just trying to come out and stay within my skill set," Sullivan said. "I'm not going to try to do too much or be a player that I'm not. I'll look to do situational hitting, and whatever I can contribute on the bases, I will."
Regardless of how he plays, Sullivan may be in for just this one start. The team is expected to call up left-hander Jon Niese for Saturday's game and send Sullivan back down to Triple-A. Nieve had been slated for that outing before sustaining his injury.
"It's exciting," Sullivan said of making his first Mets start. "I'm anxious to have an opportunity up here, as short-lived as it may be."
Mark Selig is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.