TUCSON, Ariz. -- Taylor Buchholz had a strong second outing in a Rockies uniform Sunday night after an inauspicious debut Wednesday, when the right-hander gave up four runs on six hits and a pair of wild pitches in two innings against the White Sox.

With the butterflies out of his system Sunday, Buchholz showed the kind of promise that made him a vital part of the Jason Jennings trade during the offseason. Buchholz entered a wild, sloppy 13-7 game in the seventh inning and pitched three innings of one-hit ball, shutting down the A's and earning a save for his three-frame outing.

"The first time I was just trying to get that feeling out there, trying to get [over] that first game adrenaline, trying to do a little too much," Buchholz explained Monday morning. "Last night when I got out there, it was much more relaxed. I was trying to stay within myself, trying not to do too much. Just let everything come together."

Of the nine outs Buchholz recorded, five were groundouts, two were strikeouts, and one was a popout in foul territory to the catcher. Only one ball left the infield in his three innings on the mound.

"He was able to slow things down," manager Clint Hurdle observed. "His pitches were crisp, his fastball location was good, his breaking ball was sharp. He fielded his position. [He had] better rhythm. A lot of steps in the right direction for him."

The 25-year-old clearly understood the adjustments he needed to make after his first outing, bringing a different mindset to the mound and showcasing his potential.

"It's really [about] relaxing and not trying to do too much," Buchholz explained. "When I try to do too much, I kind of tighten up. Everything flattens out and gets up in the zone. I was able to finish more down in the zone at the knees [Sunday] night."

Despite closing the game's final three innings, Buchholz remains on a pitching pace designed to prepare him for starting games, whether for the Rockies or Triple-A Colorado Springs.

The times they are a changeup: Two Rockies starting pitchers found good fortune by virtue of the changeup, with Aaron Cook brandishing the pitch Sunday night in victory over the Diamondbacks and Ubaldo Jimenez baffling the White Sox with the pitch in a Monday afternoon loss.

Cook was effective in mixing in a good number of changeups in his Sunday night start. Cook, a noted sinkerballer, has worked to expand his repertoire and confound expectations by utilizing his four-seam fastball, and the abundance of changeups Sunday gave him another tool to use against hitters.

"I'm feeling more comfortable throwing it to righties and lefties now," Cook said. "It's a big change of speed for me. I'm being powerful with it. I think that's the biggest difference. Instead of just saying this is a finesse pitch, it's a power pitch for me."

Despite being happy with Cook's outing, Hurdle cautioned against making too much of the righty's experimenting in the safety of Spring Training.

"I'll be encouraged when he takes it into the season," Hurdle said. "A lot of people try it in Spring Training. A lot of people, when it comes time for them to ring the bell, they kind of fall back in their own way. He threw some excellent changeups to some right-handers. I like him doing what he's doing."

Jimenez, on the other hand, was not trying to experiment as so much as he was trying to expose his strengths to the Rockies management.

"I'm trying to get everybody out," Jimenez said after his three innings. "When you make your pitches, things that you need to work on, you want to get guys out."

For Jimenez, the changeup is already a strength, and he used the offspeed pitch to fool the Rangers, striking out three with the same out-pitch.

"My changeup was unbelievable," Jimenez said. "They were looking for fastballs. The changeup was good."

While the changeup is already a proven pitch for Jimenez, Hurdle was quick to highlight the progress the 23-year-old has made over the past year.

"A year ago in Spring Training, when he was losing a hitter, he lost a hitter," Hurdle said. "Now, if he goes 2-0, he comes back with a strike. He gets a swing, a ball in play. He doesn't get rattled. You don't see him go quicker, harder, faster. He'll step off, he'll regroup on his own. There's more crispness to his pitches and there's more command of all his stuff."

Plan B: The Rockies and White Sox played a "B" game Monday morning, and the Rox were shut out at the Tucson Electric Park complex. Jeff Francis started the game, going three innings and letting up one run on three hits and a walk. The decisive rally included a Jim Thome double and a bases-loaded sacrifice fly from backup catcher Toby Hall. Ryan Spilborghs led the Rockies' offense, going 2-for-3 and stealing a base.

Fuentes fine: Closer Brian Fuentes downplayed being scratched from Sunday night's game with mild lower back spasms. Fuentes missed 62 games with a strained back muscle in 2004 and missed a couple of games in April 2006 with back spasms.

"It's nothing like that," Fuentes said, distinguishing the current condition from his past back issues. "It's just tight. I could have thrown, but there's no point in throwing right now."

On deck: Rodrigo Lopez takes the mound Tuesday against Javier Vazquez and the White Sox in a 1:05 p.m. game MT at Tucson Electric Park.