Rockies option lefty reliever Roberts to Triple-A

DENVER -- The Rockies optioned left-handed relief pitcher Ken Roberts to Triple-A Albuquerque on Monday. The move clears a roster spot to activate right-handed pitcher David Hale -- who will start Tuesday night against the Nationals at Coors Field -- but no official announcement has been made.

Roberts has been called up twice, and he's 0-1 with a 5.79 ERA in nine games. Colorado recalled the 27-year-old rookie on Friday, when it sent down righty starter Eddie Butler. Roberts gave up one run on one hit in one-third of an inning, taking the loss in Friday's 9-5 decision against the Padres. Roberts is 1-3 with a 4.55 ERA in 21 relief appearances at Albuquerque.

Hale, who was obtained during the offseason in a trade with the Braves, missed 5 1/2 weeks with a right groin strain. The 27-year-old is 3-4 with a 5.69 ERA in nine games (eight starts).

Video: ATL@COL: Hale exits the game in the 3rd inning

At 20 games under .500, the Rockies are hoping to establish a competitive rotation for 2016. Hale, a spot starter with the Braves in 2013 and '14 (eight starts in 47 appearances), has been given a chance to prove himself as a Major League starter.

However, injuries have been an issue. Hale suffered an oblique strain late in Spring Training, and he didn't make his debut for Colorado until May 23. And the second injury in July further slowed Hale's learning curve. During his injury rehab assignment, Hale went 0-1 with a 9.00 ERA in three games.