"Rockies manager Jim Tracy announced before Sunday's game against the Cubs that staff ace Aaron Cook's next start will be pushed back. Cook was slated to start Tuesday against the Pirates but will now pitch on Saturday against the Marlins. The right-hander suffered a hyperextension of the right big toe in Thursday's 3-1 loss to the Phillies when he was backing up third base on a Jimmy Rollins triple in the fifth inning. Cook said the toe began to irritate him in New York, which was the first stop during the Rockies' recent 10-game road trip. Cook said he feels discomfort when his right foot is pushing off the pitching rubber. He will see a foot specialist Monday. "As you're pushing off, it's just in that joint in the big toe," Cook said. "It makes it tough to push." The club is approaching Cook's injury with caution, similar to the way it handled Jason Marquis' blister on the middle finger of his throwing hand. Last month, Marquis went nine days between starts so new skin could grow on the injured finger."