The Rockies also selected the contract of reliever Wilton Lopez from the Sky Sox.
To make room for Friedrich and Lopez on the roster, the team optioned utility player Kyle Parker and reliever Chris Martin to Colorado Springs. The Rockies also transferred outfielder Michael Cuddyer to the 60-day disabled list. Cuddyer has been out since early June with a fractured left shoulder.
Friedrich missed most of last season with back inflammation.
The 26-year-old Friedrich was the 25th overall pick of the Rockies in 2008. He was 1-8 with a 7.89 ERA for the Sky Sox this season.