In order to add Morimando to the roster, the Indians designated utility man Michael Martinez for assignment.
Morimando, 23, was added to the 40-man roster over the offseason and has logged 16 starts this season for Double-A, posting 10-3 record with a 3.09 ERA. While the lefty is on full rest -- he last started on Monday -- Cleveland opted to stash him in the bullpen in preparation for his Major League debut.
In Friday's 2-1 win, the Indians used eight relievers, including Saturday's originally-planned starter, Trevor Bauer, for the final five innings.