Brandon Cumpton will start on tomorrow, taking Wandy Rodriguez's place in the rotation. Cumpton last pitched on May 20, so he'll get five days of rest before his return to the big leagues.
Cumpton has an odd history of pitching better in the majors than he has in the minors, but even if his minor league performances are more representative of his true talent level, he's done a great job improving his control over the past year or so, and he's always been good at generating ground balls. He's worthy of the chance he's about to get. With Rodriguez gone and with Jameson Taillon not a factor this season, there's no reason Cumpton can't nail down a rotation spot for the foreseeable future if he pitches well.
Jeff Locke has pitched fairly well for Indianapolis, but not as well as Cumpton. He'll remain there for the time being.
The Pirates are currently carrying eight relievers, so they'll likely send Jared Hughes back to Indianapolis tomorrow as the corresponding move.