Wanting to bolster their bullpen with a left-hander, the Rockies called-up Josh Outman from Triple-A Colorado Springs Friday afternoon and optioned right-hander Chris Volstad to the Sky Sox. Outman will be available for Friday night’s game against the Diamondbacks.

Manager Walt Weiss said the Rockies need a left-hander in the bullpen, especially with the Rockies beginning a three-game series with the Diamondbacks Friday night, and with the high-flying Braves coming to Denver on Monday. Weiss said Outman will be used in both short stints and long relief.

Outman, who failed to make the big-league roster in spring training, has been impressive in Triple-A this spring, posting a 0.84 ERA in five appearances. In 10 2/3 innings he’s struck out 14 and walked just three.

“He’s been throwing strikes and he’s been very effective,” Weiss said. “We talked with Josh this spring about pitching to the bottom of the zone. He’s got big arm, and it’s a tough job for every left-handed batter facing Josh. He went down there and got off to a great start. He’s thrown strikes and been effective. He’s got the ability to help us.”

Though Volstad struggled, posting a 8.53 ERA in four appearances, Weiss said he didn’t consider the move as a demotion for Volstad.