"Aaron Cook had that sinking feeling in the first inning Sunday against the Tigers. That was a good thing, and it produced three groundball outs.

It's when he started elevating the ball that the Rockies pitcher found trouble.

"After that first inning I started throwing my sinker flat and leaving it up a little bit," said Cook, who allowed four runs and eight hits in six innings in his third start of the season since coming off the disabled list.

Cook began using his off- speed pitches after the first inning, with mixed results.

"I started to use my slider and curve a little bit," he said. "My secondary pitches have been working really good for me, and I've worked really hard on them."

But Cook (0-2, 4.67 ERA) admits he's a work in progress.

"I'm a pitcher right now that doesn't get away with mistakes," he said. "I made some mistakes today, and they made me pay for it.""