DENVER -- The Pirates postponed Gerrit Cole's next start, as they attempt to reduce the workload of their rookie entering the final seven weeks of the season, manager Clint Hurdle said Sunday.

Cole will start Friday at home against the Arizona Diamondbacks. His turn in the rotation would have been Wednesday against the Cardinals in St. Louis, but the scheduled day off today allowed the Pirates to push back his outing.

"Through our projections, we want to make sure that we keep things where they need to be," Hurdle said.

Francisco Liriano will start Wednesday and A.J. Burnett will start Thursday, both on regular rest. Charlie Morton will open the series Tuesday.

Cole has thrown 134 innings in 23 starts between the majors and Class AAA Indianapolis this season. He threw 132 innings in 2012, his first full season in professional baseball, plus his work in the instructional league after the season.

"He's one of the few guys that's going to go from instructional league to hopefully the postseason [the] next year," general manager Neal Huntington said.

Cole threw a bullpen session Sunday at Coors Field. He will throw another in St. Louis, Hurdle said, possibly against batters.

"He'll make three starts through the end of the month instead of four, so we knocked an entire start out, knocked another hundred pitches off the plate," Hurdle said. "We'll look to trim in other places as well."

Starling Marte did not start Sunday, one day after leaving the game when he took a pitch off his left hand. He appeared to have escaped serious injury, though.

"We're of the mindset that we're going to be able to have a better read after today," Hurdle said. "We have a day off tomorrow. There wasn't anything saying, screaming at us, that he's hurt and is going to be out awhile at this point."

Marte had an ice pack on his hand in the clubhouse Sunday before the game.

Alex Presley led off and started in left field.

Wandy Rodriguez remains on track to throw a bullpen session Wednesday, followed by a live batting practice session Friday or Saturday, Huntington said.

Rodriguez said he had no problems with his left forearm after throwing a bullpen session Saturday.

"He'll throw a couple sides and see how the sim game, BP segment of his goes," Huntington said. "Then how quickly can we get him out in a rehab."

James McDonald threw a bullpen session Sunday, Huntington said, and is scheduled for a simulated game this week. Huntington said McDonald would pitch in relief if he returns this season.

The Pirates knew they would have trouble claiming players off waivers this August, as their record would allow almost every other team to block a player from reaching them. But Huntington said teams have put fewer players on waivers this season, and of those on waivers, more have been claimed.

"As we look at the list of guys who have cleared, it's shorter than I remember it being at this point in time," he said. "Of the guys that we've placed claims on, fewer and fewer are getting to us."