Outman has looked sharp in Triple-A so far this season, only allowing two runs over 10.2 innings in five appearances. The southpaw has struck out 14 batters and walked three.
Rockies manager Walt Weiss told the media that Outman will be used in both short relief and long relief. Colorado also hosts the left-handed heavy Arizona Diamondbacks over the weekend, and Weis wanted a left-handed reliever in the bullpen.
Outman pitched for the Rockies last season, but struggled mightilty. The southpaw made seven starts for Colorado and 20 appearances out of the bullpen, posting an 8.19 ERA in 40.2 innings. Outman has been able to post strong strikeout numbers when pitching out of the bullpen but battled his control last year, waling 4.43 batters per nine innings.
Volstad, a former starter for the Miami Marlins and Chicago Cubs, had pitched poorly in four appearances out of the Rockies bullpen. The right-hander did not increase his strikeout rate in the transition, only fanning 4.26 batters per nine innings, and had a 8.53 ERA.