Morel was hitting .273 with four home runs and 52 RBIs in 92 games at Indianapolis. He also hit .143 with three RBIs in 12 games with the Pirates earlier this season.
Left-hander Jeff Locke was optioned to Indianapolis in a procedural move. He will remain with the Pirates and be recalled Monday when the major league roster limit expands from 25 to 40. Locke is scheduled to start Tuesday night at St. Louis.