"There's no sugar-coating it," Tracy said. "We did not play well tonight."
Cook gave up three first-inning runs. He left after walking Nate Schierholtz to open the fourth. Josh Fogg replaced him. Ian Stewart, who moved from third base to second as part of the changes forced by Tulowitzki's absence, committed one of the Rockies' three errors on a Travis Ishikawa grounder, and Aaron Rowand followed with a homer for a 6-1 Giants lead.
But the Rockies had two on with one out in the fifth. Giants starter Jonathan Sanchez -- who struck out eight and held the Rockies to one unearned run but was gone after five innings because of a high pitch count -- forced a double-play grounder from Ryan Spilborghs.
The Rockies loaded the bases with one out in the seventh. But Giants manager Bruce Bochy went to former Rockies left-hander Jeremy Affeldt, who forced Todd Helton to bounce to the mound. Affeldt started a home-to-first double play.
Seth Smith knocked his 10th homer of the season, a solo shot off Affeldt in the eighth, and Dexter Fowler doubled and scored on Garrett Atkins' single in the ninth, but the Rockies were simply inconsistent offensively.
Add to that the errors and a couple of throws to the wrong base, and it was a winnable game the Rockies couldn't capture.
"An at-bat or two and the game changes," Tracy said.
Stewart noted that the Rockies did what they planned against Sanchez, until it counted.
"We were getting into a lot of 2-2 counts, 3-2 counts, 3-1, just like we tried to, to get the starting pitcher's count up," Stewart said. "But he made some good pitches, big pitches for himself and the team. He was able to keep us in check."
The Rockies had returned home after a 4-2 road trip had pulled them to 3 1/2 games behind the NL West-leading Dodgers. One bad night later and the Giants, who had lost a 2-1, 10-inning groaner to the Reds on the road Thursday, are breathing down their backs.
"We had a tough loss yesterday," Giants manager Bruce Bochy said. "Playing a good team here in their ballpark and to get the win was big for us."
Tulowitzki, who had not missed a start since June 6 and is a key reason the Rockies are contending, will return, according to Tracy, once the team feels he has rehydrated and is not a risk for a muscle pull.
Cook's status is not as certain, although Tracy said it was unlikely he would make his next scheduled start, Wednesday against the Dodgers.
Cook had been battling a hyperextended right big toe. His last start, a rough one Sunday against the Marlins, was backed up as a precaution, with the hope that Cook could heal and not have to alter his mechanics.
Cook said he does not believe his shoulder issue is related to the foot, and he's hoping not to go on the disabled list. Almost as disappointing as the injury for Cook was he felt he was finding his form after the three-run, three-hit first.
"I started to feel like I was in a good rhythm, getting the ball down in the zone, getting ground-ball outs like I typically do," Cook said. "Then I came out for the fourth inning and I knew something was wrong."