By C. Trent Rosecrans
Cahill and lefty reliever Craig Breslow are headed to Arizona in return for right-handers Jarrod Parker and Ryan Cook, along with outfielder Collin Cowgill. Arizona also received cash considerations in the deal.
Cahill would bolster the Diamondbacks' rotation, joining Ian Kennedy and Daniel Hudson at the top of the rotation. Cahill, 23, is signed through 2015 with club options for 2016 and 2017. Cahill is owed $30 million over the next four season, earning $3.5 million this season after making just $500,000 last season.
Cahill was 12-14 with a 4.16 ERA last season after going 18-8 with a 2.97 ERA in 2010. Breslow appeared in 67 games last season with a 3.79 ERA and has pitched in 202 games with a 3.14 ERA after being picked off from waivers by the A's from the Twins in 2009.
Parker, 23, was the Diamondbacks' first-round pick in the 2007 draft and made his big-league debut this past season, earning a no-decision in his lone start, but throwing 5 2/3 innings without allowing a run. He also made an appearance in the NLDS against the Brewers, allowing two hits and a run in 1/3 of an inning.
Cowgill, 25, hit .239/.300/.304 with a home run in 100 plate appearances last season. Cook was 0-1 with a 7.04 ERA in 12 appearances for the Diamondbacks in 2011. In his first year as a reliever, he appeared in 48 games at Double-A and Triple-A in addition to his big-league stint, earning a 2.21 ERA with 62 strikeouts in 61 innings.
"We feel very fortunate to add a young, talented started like Trevor to our rotation and an extremely durable and successful reliever like Craig to our bullpen," Diamondbacks GM Kevin Towers said in a release by the team. "It's never easy to part with a prospect, but we feel like the surplus of talent that our scouting and player development staff has generated puts us in a position to build on what we accomplished this season and truly improve our team in 2012 and beyond."
Overbay finished 2011 with Arizona after being released by the Pirates in August. He hit .286/.388/.452 with a home run in 18 games for Arizona after hitting .227/.300/.349 for the Pirates in 391 playte appearances. Overbay started his career in Arizona, playing part of three seasons there before being traded to Milwaukee in the deal that brought Richie Sexson to Arizona.For more baseball news, rumors and analysis, follow @eyeonbaseball on Twitter or subscribe to the RSS feed.