Trevor Cahill was recalled from Triple-A Reno on Monday and will start for the Diamondbacks on Friday against the Cubs at Chase Field.
To make room, the Diamondbacks optioned right-hander Mike Bolsinger to Reno.
Cahill started the season in the starting rotation but was moved to the bullpen after four rocky starts in which he was 0-4 with a 9.17 ERA and only once lasted longer than four innings.
Then a month ago the Diamondbacks sent Cahill to the minors, where he built up his pitch count and arm strength in order to return to the rotation.
Cahill made one start with High-A Visalia before moving to Reno. He had a 4.45 ERA in 30-1/3 innings in the minors, with 20 walks and 27 strikeouts.
Cahill was send to the minors with the understanding he would be brought back to the majors at a specified time, GM Kevin Towers previously said. Cahill is under contract for next season for $12.3 million.
The Diamondbacks will follow Cahill in their post-All-Star break rotation with left-hander Wade Miley and right-hander Josh Collmenter against the Cubs. Lefty Vidal Nuno and righty Chase Anderson will start against the Tigers next week.
Bolsinger, in two stints in the rotation this season, had a 5.50 ERA in 52-1/3 innings.
