It was Colorado's eighth straight defeat.
Parker, a 23-year-old rookie, allowed just three hits, struck out six and walked one. He faced the minimum number of batters in four of the seven innings he pitched.
Brandon Moss had a home run and three RBI and Josh Reddick homered for the A's, who pulled off the sweep after getting swept in a three-game set at Arizona.
'How to Train Your Dragon 2' releases 5-minute clip
Lytro unveils camera that can focus a photo after shooting it