Athletics acquired RHPs Ryan Cook and Jarrod Parker and OF Collin Cowgill from the Diamondbacks for RHP Trevor Cahill, LHP Craig Breslow and cash considerations. Cook had a successful transition to the bullpen this past season in the minors, posting a 2.21 ERA and 62/22 K/BB ratio over 61 innings between Double-A Mobile and Triple-A Reno. The 24-year-old right-hander wasn't nearly as effective in his first taste of the big leagues, posting an ugly 7.04 ERA over 12 appearances, but Oakland obviously sees something here. He'll likely compete for a bullpen job during spring training.

Diamondbacks recalled RHP Ryan Cook from Triple-A Reno. Reno spent two short stints in the big league earlier this year, surrendering four runs in 1 2/3 innings. He won't be used in high-pressure situations down the stretch.

Diamondbacks optioned RHP Ryan Cook to Triple-A Reno. He was cleared to make room on the active roster for Jason Marquis and Brad Ziegler, who were acquired over the weekend. Cook, 24, has allowed four runs over 1 2/3 innings in two brief stints with the D-Backs this season.

Diamondbacks recalled RHP Ryan Cook from Triple-A Reno. Cook was sent to the minors less than a week ago to make room for J.J. Putz, but will return to the show with Alberto Castillo (shoulder) headed to the D.L. The 24-year-old will provide middle relief depth.

Diamondbacks optioned RHP Ryan Cook to Triple-A Reno. He'll go back to the minors to make room for J.J. Putz, who is expected to return from the disabled list Tuesday. Cook was blasted for four runs on four hits and two walks over two appearances during his brief stay with the big club.

Ryan Cook will likely return to the minor leagues when J.J. Putz comes off the disabled list on Tuesday. Cook had his contract purchased from Double-A Mobile earlier this week to help provide depth in a depleted Arizona bullpen. He'll be back up in the majors when rosters expand in September, if not earlier.

Diamondbacks purchased the contract of RHP Ryan Cook from Double-A Mobile. Cook, 24, has posted a strong 2.25 ERA and 50/14 K/BB ratio in 44 innings this year at the Double-A level. The D'Backs will hope that he can now replicate that success in the middle of their major league bullpen.