The Rockies designated Blalock for assignment Thursday, Patrick Saunders of The Denver Post reports.
The club needed to free up a spot on its 40-man roster for the addition of Michael Lorenzen, whose signing was officially announced Thursday. Blalock has been dreadful in the big leagues to this point, posting an 8.16 ERA and 47:43 K:BB over 89.1 innings in parts of two seasons. Perhaps another team believes it can coax more out of him outside Colorado, but it's likely he will clear waivers.