Regardless of the NL West race by the time the Rockies get to Arizona, Cook felt he made the necessary decision in turning down a fifth chance to claim that elusive 17th victory.

"I would expect to have a shot at 17 wins again in my career," he said. "I don't feel the risk is worth the reward. I talked with (manager Clint Hurdle) and (pitching coach Bob Apodaca), my family and my teammates before deciding this was the right thing to do."

While he said he has overcome the back spasms that forced him to take eight days between starts in mid-August, he did admit some tightness in getting loose for his two previous starts.

"It is more important to go into the offseason healthy and build up for next year," Cook said. "I've hit the point in the season where there have been a lot of innings."

Cook has a career-best 16 victories in 32 starts. He worked 211 1/3 innings, four outs shy of his career high from 2006.

ROCKIES 9, GIANTS 4: Troy Tulowitzki was 4-for-5 with a home run and two-run, go-ahead single in the fourth. Tulowitzki raised his season average to .260, the highest it has been since he was hitting .375 after the second game of the season. Seth Smith also homered off Tim Lincecum, and he doubled and scored on the Tulowitzki groundball to give the Rockies a 4-3 lead in the fourth.

The Rockies snapped a five-game road losing streak and extended their edge on the Giants in the battle for third place in the NL West to two games with five games to play.