St. Louis Cardinals closing pitcher Jason Motte emerges from the clubhouse before a game between the Colorado Rockies and the St. Louis Cardinals at Busch Stadium in St. Louis on May 10, 2013. Motte has undergone Tommy John surgery and will not pitch until next year.       UPI/Bill Greenblatt

Jason Motte emerges from the clubhouse before Sunday’s game. Motte has undergone Tommy John surgery and will not pitch until next year. UPI/Bill Greenblatt

Lefty John Gast will make his big league debut filling in for Jake Westbrook, who is on the 15-day disabled list with elbow inflammation. Gast was 3-1 with a 1.16 ERA at Triple-A Memphis and did not allow an earned run over his first 32 innings this season and was the Cardinals Minor League Player of the Month for April.

The Cardinals placed Westbrook on the DL retroactive to May 9. Jason Motte will be moved to the 60-day disabled list to make room for Gast. Motte is done for the season after having Tommy John surgery.  Westbrook was 2-1 with a 1.62 ERA over seven starts for the Cardinals in 2013 and led the National League in ERA after the month of April.