Snell (4-8) gave up four runs on eight hits. He walked one and struck out eight in seven innings for his first win since June 11.
Valerio De Los Santos started for Colorado in his first appearance in the major leagues since 2005, and his first MLB start since 2000. He gave up two runs on two hits and six walks in four-plus innings.
Jason Grilli (2-2) took the loss after allowing two runs in one inning.
Matt Holliday hit a two-run homer and Willy Taveras had two hits and an RBI for the Rockies, who ended a five-game win streak.