Pollock singled to lead off the 10th against Edgmer Escalona (1-1) and took off for second as Paul Goldschmidt struck out swinging. Catcher Wilin Rosario's throw sailed past the bag, allowing Pollock to go to third.
After Miguel Montero was intentionally walked, Ross lofted a fly to center to drive in the winning run.
Ross also provided an RBI triple while Pollock went 3-for-5 with a homer as Arizona registered its fourth victory in five games.
J.J. Putz (2-0) hurled a 1-2-3 top of the 10th to earn the win.
Rosario went 3-for-4 with a homer and Troy Tulowitzki added two hits with a pair of RBI for the Rockies.