The Diamondbacks purchased the contract of reliever Chaz Roe from Triple-A Reno to take Cahill’s place.
Cahill was hit by a line drive off his hip during the first inning of his start on June 19. Cahill was taken out of the game three pitches into the next inning.
Since then, Cahill has made his two scheduled starts but has been roughed up.
The 25-year-old went 0-5 in six June starts with a 9.85 ERA.
Arizona is likely to call up either Tyler Skaggs or Charles Brewer from Reno to make Cahill’s next start on Friday.
For the season, Cahill has compiled a 3-10 record to go along with a 4.66 ERA and a 1.41 WHIP.
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John Newsome and Anne Woolsey, CNN