The Rockies recalled Blach from Triple-A Albuquerque on Tuesday.
The left-hander was demoted July 17 despite allowing just one run in 6.1 innings across his last three big-league appearances. Overall, Blach has a 5.73 ERA and 1.35 WHIP in 18 games (one start) for Colorado this season and figures to see some middle-relief work going forward.