In a corresponding roster move, the Rockies recalled right-hander Guillermo Moscoso from Triple-A.
Ekstrom appeared in fifteen games for the Rockies this season. The 28-year-old maintained an ERA of 6.32 over fifteen and two-thirds innings of work with 5.2 SO/9 and 1.1 BB/9.
Ekstrom signed with Colorado this off-season after spending two years apiece at the major league level with the Tampa Bay Rays and San Diego Padres. He owns a career ERA of 5.61.
The Rockies acquired Moscoso from the Oakland Athletics in January as part of the Seth Smith trade. The 28-year-old has appeared in ten games, including two starts, for Colorado this season, maintaining an ERA of 8.23 with 10.2 SO/9 and 3.6 BB/9.