The move comes after right-hander Bronson Arroyo went on the disabled list for the first time in his long career. Tests showed he has a sprained ulnar collateral ligament in his right elbow.
Bolsinger was 1-2 with a 6.08 ERA in five games, four as a starter, with Arizona earlier this year. At Triple-A Reno, he is 5-1 with a 2.73 ERA in nine starts.
The team optioned right-handed reliever Will Harris to Reno. Harris was 0-2 with a 9.24 ERA in two stints with the Diamondbacks this season.