 Perez signed a minor league contract with the Philadelphia Phillies before the 2011 season.He had his contract purchased on June 23.Pérez pitched an immaculate inning in the 10th inning in a win against the Braves on July 8, 2011, striking out the side in 9 pitches, making him the second Major League pitcher to ever pitch an immaculate inning in an extra inning of baseball.