The 25-year-old Cabrera suffered a slight strain of his left hamstring while running out a sixth-inning groundout in Game 4 of the Fall Classic on Sunday, and manager Joe Girardi said he was "very limited" on Monday, as the Yankees look to defeat the Phillies and finalize their first title since 2000.
MLB postseason rules provide that injured players can be replaced during the World Series if the severity of the injury, as determined by MLB, is such that it would require a disabled list assignment during the regular season. Had this been the regular season, Girardi said that Cabrera would have been out of action for "maybe a couple of weeks."
"He did it playing hard, and that's usually how it is," Girardi said.
The Yankees selected Pena, a 23-year-old rookie, over outfielder Freddy Guzman and catcher Francisco Cervelli, who are also with the team and were considered for the roster spot.
Cabrera had started all 13 of the Yankees' postseason games this year in center field and was batting .154 (2-for-13) with a run scored and three strikeouts in the World Series.
The switch-hitter batted .271 (13-for-48) with five runs scored, two doubles and four RBIs in the postseason after batting .274 with 13 home runs and 68 RBIs in 154 games for the American League champions, setting career highs in doubles (28) and homers.
"He had an outstanding year," Girardi said. "I thought he grew up a lot this year. He matured as a player and became dangerous from the right side as well as the left side. He did so many good things for us. He was the start of the walk-off hits, really. It's unfortunate."
Pena batted .287 (33-for-115) with 17 runs, six doubles, and 10 RBIs in 69 games for New York over three stints in 2009. He made 14 starts at third base, 11 at shortstop and three at second base.
Bryan Hoch is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.