The Diamondbacks will open a series against the Dodgers tonight with a rotation that has produced a combined 6.57 ERA that trails only the Twins for the worst mark in Major League Baseball, but general manager Kevin Towers tells MLB.com's Steve Gilbert that he's not actively pursuing trades of pitchers at this time (Twitter link). However, he does expect to sign a veteran starter to serve as depth at Triple-A in the coming days.
As the Arizona Republic's Nick Piecoro wrote this week, Josh Collmenter seems likely to be headed into the rotation in place of either Randall Delgado or Trevor Cahill (and that was written prior to another poor outing from Delgado last night). That might provide an upgrade, but it's not the most impactful move that the club could make. Top prospect Archie Bradley is looming at Triple-A Reno, where he tossed five shutout innings in his first start of 2014. Bradley would need to remain in Triple-A through late April to delay his free agency another season or stay in the minors through June to avoid Super Two status. CEO Derrick Hall recently told fans that service time isn't a consideration, and Bradley is "exactly where he should be right now to fine tune some skills and work on his command." (Of course, those comments are the expected refrain from an executive.) Gilbert tweeted to one of his followers that there has been no mention of Bradley being promoted as of yet.
A look at the remaining free agents shows that Towers and his baseball operations staff don't have a lot to choose from in terms of starting pitchers. Freddy Garcia would make sense, but he's said that he would prefer retirement to pitching in Triple-A, making him an unlikely fit as minor league depth. Jair Jurrjens could have the most upside of the group. He underwent knee surgery last September but should be recovered based on the timeline tweeted by Yahoo's Tim Brown this winter. Those two names are pure speculation on my part.