Manager Bud Black confirmed that Feltner will be called up from Triple-A Albuquerque to start Wednesday's game in Pittsburgh, Patrick Saunders of The Denver Post reports.
Colorado will likely wait until Wednesday to officially add Feltner to the 26-man roster while removing another player from the roster in a corresponding move. Feltner previously made a spot start for the Rockies on April 27, when he took a loss in Philadelphia after giving up four earned runs and struck out seven over five innings. His most recent appearance in the minors was a three-inning outing Saturday, so Feltner could face some light restrictions with his workload Wednesday while taking the hill on three days' rest rather than the standard four. Feltner's stay in the Colorado rotation is unlikely to last more than a week or two, as Antonio Senzatela (back) is close to heading out on a rehab assignment and should be ready to return from the 10-day injured list by early June to reclaim his starting role with the big club.