Remember back on May 16th, when I wrote a post about what might happen if the Diamondbacks become trade deadline sellers? They lost that day, then promptly won 13 of 14 games. The first-place D'Backs are a half-game ahead of the Giants, and ESPN's Buster Olney tweets that they'll be aggressive before the trade deadline and are poised to spend.
Starting pitching could be considered a need for the D'Backs. Their starters have a cumulative 4.20 ERA, which ranks 12th in the National League. The rotation is led by Ian Kennedy and Dan Hudson. Southpaw Joe Saunders has struggled, and despite an improved ERA in May his peripheral stats suggest his 4.77 ERA might not get much better. Still, I think he'll remain in the rotation.
After those three it's Zach Duke and rookie Josh Collmenter. Duke was excellent in his Saturday season debut and should have a fairly long leash in the rotation. Collmenter has pitched well in three of four starts. Right now GM Kevin Towers is probably thinking if it ain't broke he won't fix it, and obvious upgrades will be hard to come by on the trade market. Back on May 11th, when Collmenter joined the rotation, Towers told Nick Piecoro of The Arizona Republic that his first choice is to look in-house, but they're exploring external options as well. He's got two full months prior to the trade deadline to determine the staying power of the current starting five.
Arizona's bullpen has been strong this year, but Towers should be proactive in adding reinforcements. The pen is built around J.J. Putz and David Hernandez. Putz must be handled with care - he hasn't pitched three days in a row since August of last year. And while Hernandez has been a big addition, walking 5.9 batters per nine innings is rarely a sustainable approach. Sam Demel and Juan Gutierrez are on the DL and Collmenter is in the rotation, leaving Joe Paterson, Esmerling Vasquez, Aaron Heilman, Zach Kroenke, and Micah Owings to round out the pen. Paterson and Vasquez have been useful, but this bullpen could use more depth.
Offensively the Diamondbacks are strong; they rank third in the league with 4.78 runs per game. Of course, you can never score too many runs, so Towers could consider left field upgrades if he'd like to push Gerardo Parra to a fourth outfielder role. But if Towers wants to swap defense for offense in left field, he can just call up Wily Mo Pena.
A team that is "poised to spend" would match up well with the Mets, who have useful but expensive players in Carlos Beltran and Francisco Rodriguez. The Twins are another likely seller with several players who would fit with Arizona. Towers is in a good position - his team's needs are not desperate, and if he can take on salary that will set him apart from many other buyers.