Mock made one appearance earlier this year, but was optioned back down to make way for Triple-A teammate Tyler Clippard. Mock will make a spot start for Perez, who's still recovering from left shoulder tendonitis.
Since being called up on May 23, Langerhans has notched 30 at-bats and a .200 batting average in 23 games. Additionally, he played 67 innings wihtout an error as a reserve outfielder.
Zachary Osterman is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.