DENVER -- The Braves have optioned Tommy Hanson to Class A Advanced Myrtle Beach and added Luis Valdez to their bullpen mix for this weekend's series against the Rockies at Coors Field.

With Javier Vazquez's lower abdominal strain making him unavailable, Kris Medlen will start Sunday's series finale. Consequently, Medlen won't be available to serve in his long relief role on Friday and Saturday.

"We didn't have enough pitchers to get through this series," Braves manager Bobby Cox said. "Sometimes the games can get out of hand here in Colorado and you use up all of your pitchers."

Valdez, who has posted a 3.00 ERA and notched 16 saves in 37 appearances with Triple-A Gwinnett this year, will provide the bullpen with some much-needed depth. Having pitched each of the previous three days, left-handed reliever Mike Gonzalez will likely be unavailable for Friday night's game.

Hanson, who is 4-0 with a 2.85 ERA through the first seven starts of his career, will be eligible to be promoted back to the Majors in time to make his first scheduled turn after the break.

As long as he's healthy enough to pitch, Vazquez could face the Mets on July 19 and Hanson could start the series opener against the Giants the next day.