Houston, TX (SportsNetwork.com) - The Arizona Diamondbacks have optioned right-hander Trevor Cahill to Single-A Advanced Visalia.
The club designated Cahill for assignment on Monday after he struggled in both the rotation and bullpen this season, going 1-6 with 5.66 earned run average in four starts and 15 relief appearances.
Cahill, 26, was the centerpiece of a December 2011 trade that sent Ryan Cook and Jarrod Parker to Oakland. He finished in the top 10 in AL Cy Young voting after going 18-8 with a 2.97 ERA for the Athletics in 2010.
The Diamondbacks also announced Thursday that they have claimed infielder/catcher Jordan Pacheco off waivers from the Colorado Rockies.
Pacheco batted .236 in 22 games for the Rockies this season.
Infielder/outfielder Nick Evans was designated for assignment to make room for Pacheco, a career .281 hitter in 270 games with Colorado.