Three weeks after his last appearance for the Colorado Rockies, Aaron Cook will make his first rehab start tonight for Double-A Tulsa.

Christian Friedrich left his start Wednesday at Tulsa three hitters into the third inning after suffering a strained lat muscle. Tyler Matzek also had a short outing at Asheville, but his early exit was based on pitch count.

Jhoulys Chacin and Christian Friedrich are scheduled to start Saturday at Triple-A Colorado Springs and Double-A Tulsa respectively.

Todd Helton will drive to Casper on Thursday and play three games there Friday, Saturday and Sunday on a rehab assignment with the Colorado Rockies affiliate in the Rookie Pioneer League.

Christian Friedrich (left elbow contusion) is expected to miss no more than two starts for Modesto, and Samuel Deduno (stress fracture right elbow) is scheduled to begin a rehab assignment at Tri-City.

Colorado Rockies left-handed pitching prospect suffers contusion when struck on left elbow in first inning Sunday night at Double-A Tulsa.

Left-handed pitcher Christian Friedrich and catcher Wilin Rosario, top Colorado Rockies prospects currently playing at Double-A Tulsa, have been named to the rosters for the 2010 Futures Game.

Colorado Rockies left-handed pitching prospect Christian Friedrich is scheduled to start Friday for Double-A Tulsa after missing nearly a month with inflammation in his left elbow.

Shortstop Chris Nelson will join Triple-A Colorado Springs on Saturday. Left-hander Christian Friedrich should return to the Double-A Tulsa rotation in about 10 days. And Greg Reynolds will start Saturday for high Class A Modesto.

Soreness in left elbow sidelines Colorado Rockies pitching prospect

Esmil Rogers returned to the starting rotation Monday at Triple-A Colorado Springs after spending most of the first two weeks of the season in the Colorado Rockies bullpen.

Colorado Rockies pitching prospects Jhoulys Chacin and Christian Friedrich both pitched solid games in their season debuts Thursday.