Colon (9-2) racked up a sixth win in six starts, limiting the Mariners to two runs on eight hits. The veteran right-hander didn't issue a walk and struck out three as the A's avoided a three-game sweep.
Reddick's run-scoring single in the fourth forged a 2-2 tie and his solo homer in the ninth capped the scoring as Oakland pounded out 17 hits.
Seattle's Hisashi Iwakuma (7-2) gave up four runs on eight hits in five innings.
Endy Chavez drove in both Mariners runs.
2014: The Year in Music [PHOTOS]