Rocker is competing with Jack Leiter to fill the spot in the Rangers' rotation vacated by Cody Bradford (elbow), Evan Grant of the Dallas Morning News reports.
The former college teammates and current pro teammates will go head-to-head for the right to serve as the Rangers' fifth starter while Bradford recuperates from left elbow soreness. Rocker has been blasted for eight runs over two innings in his two Cactus League starts this spring, but he threw three hitless frames in an intrasquad game last weekend. Leiter, meanwhile, has pitched much better with a 2.53 ERA and 13 strikeouts over 10.2 innings, although he was shaky his last time out. It's unclear which of the two righties might have the current edge, but with the injury history of some of the other Rangers starters, there's a decent chance both Rocker and Leiter will wind up spending a significant portion of the season in the Texas rotation.