DENVER -- Trevor Cahill only gave up one run over six innings in his first start in a D-backs uniform last Tuesday, but he was less than pleased with the six walks he gave up.

In looking back over the start, Cahill did not find anything he could correct for Sunday when he takes the mound against the Rockies.

"I didn't see any big differences mechanically or anything," Cahill said. "Sometimes you feel where it's coming out, sometimes it just comes out different every time."

So what does he do when something like that happens during the game?

"I've had my share of games where I didn't know where it was going," Cahill said. "But you just have to battle through it and hope you figure something out, or something clicks. It definitely makes it tough."

Upton wisely using speed to get on base

DENVER -- Justin Upton took advantage of what the Rockies defense gave him on Friday night, when he bunted for a base hit.

"It's smart," D-backs manager Kirk Gibson said. "Make them come in there and they have to respect him. Works good, and you always feel better when you get a hit, no matter how you get a hit."

If Upton were to do that a few times, would opposing teams start pulling the third baseman in against him?

"I don't think so, not much," Gibson said. "The reality of it is they'd rather he bunt than hit the ball out of the park. Early in the season, he hasn't driven the ball. He doesn't have a home run in spring or here. So it's the smarter play right now, but I think in general he has a chance to hit the ball out of the park, [so] they'd almost concede that."

Upton jammed his left thumb while sliding into second base in the third game of the season, and that has hampered him of late.

"His thumb is what it is," Gibson said. "I think he's understanding more how to deal with it. He just kind of understands what to expect. I'd like to just see him get locked in. Not to put pressure on him, but when he does it takes a lot of pressure off our offense, everyone seems to fall into place, because he has such a huge impact in the way he drives the ball and the way he pressures the defense."