 Pérez was not expected to be a major part of the Indians' major league club in , but he surprised the Indians organization after he was called up from the team's Triple-A affiliate, the Buffalo Bisons, on May 28.Pérez was initially slated for long relief, but after he demonstrated his ability to pitch in tight situations, he was inserted into a setup role alongside right-handed reliever Rafael Betancourt.The two setup men were nicknamed Raffy Left and Raffy Right by local Indians fans.