Feltner was scratched from his scheduled start Saturday against Atlanta due to an illness, Thomas Harding of MLB.com reports.
Manager Warren Schaeffer said that Feltner spent much of Friday night vomiting, so the Rockies will pull him off his start and instead send Zach Agnos to the mound in the first inning. Feltner could still be available out of the bullpen if he manages to arrive at the park before the end of the game.