Ubaldo Jimenez strolls around the clubhouse with a carefree attitude even if he's smoldering inside.

The Colorado Rockies All-Star pitcher is baffled by his puzzling plunge in production this season, a slump that's tested his usually easygoing demeanor.

This time last year, Jimenez was putting up numbers that vaulted him into the conversation as one of the game's best pitchers.

Now, he's mired in a skid that has his record at 1-7, his ERA at 4.63 and everyone wondering: Where's Ubaldo of last year?

Always the optimist, Jimenez believes he's close to recapturing that form. By poring over game film from last year, and paying close attention to every aspect of his unorthodox delivery, Jimenez thinks he's uncovered some tiny flaws.

Not only that, but the zip on his fastball has steadily returned with the weather warming up. The 27-year-old Dominican flamethrower hit 99 mph with a pitch against the Los Angles Dodgers on Sunday.

To him, that's an encouraging sign.

"I'm getting the strength back in my arm. I'm throwing lower strikes," said Jimenez, who will start Saturday night in an interleague game against the Detroit Tigers. "Once I get everything together, throwing strikes and getting my velocity back, I'm going to be good."

Jimenez insists his arm feels fine. And while he contended with a bothersome cracked cuticle on his pitching thumb early in the season — landing him briefly on the disabled list — there's no lingering issues.

His biggest hindrance has been trying to consistently locate his fastball that dances and dives. Part of that has to do with his arm slot being out of sync, leading him to release the ball from different points every time he winds up. He's attempting to iron that out in bullpen sessions, with pitching coach Bob Apodaca watching over his shoulder.

Apodaca thinks Jimenez is on the verge of coming out of his funk.

"I'm kind of liking the direction he's going," Apodaca said. "We just keep working hard whether he's going bad or whether he's going well. We keep working on the fundamentals."

That's the thing about Jimenez: No matter how disgruntled he becomes, he keeps irritation at bay — or tries to anyway. In times like this, his happy-go-lucky attitude comes in handy.

Once he takes the mound, though, that demeanor ends and he's all business.

"He's an easygoing guy in the clubhouse. He's not an easygoing guy out there," Apodaca said. "Don't misinterpret nice from being a competitor. There is as much fire in him even with an easy facade."

After each home start, Jimenez will walk the few blocks to his downtown residence, allowing himself to fume about his performance. And there's been a lot of seething this season, especially since he's 0-5 with a 7.05 ERA at Coors Field.

Once he reaches the front door, it's out of his mind. His rule for himself is simple: No taking the game home with him, no matter how upset he becomes.

"You're going to have ups and downs," Jimenez said. "Everything is not going to be the same every year."

Jimenez wishes that were the case. He rewrote the Rockies record book last season, setting new marks in wins (19), ERA (2.88) and strikeouts (214).

Jimenez was so good in early 2010 that not only did he throw the team's first no-hitter on April 17 in Atlanta, but he was in the midst of a season for the ages. He became the first NL pitcher in nearly a century to win 13 of his first 14 starts, earning him the start at the All-Star game.

But after the midseason break, he was hardly the same, going 4-7 with a 3.80 ERA.

His struggles have spilled into 2011 as he searches to regain the form that had hitters cursing his command and completely guessing at what he might be throwing from his five-pitch repertoire.

"It hasn't been the easiest in the world for him up to this point," Rockies manager Jim Tracy said. "But he's the same guy every day. Five days from now, he will be going out there to do his thing and try to put us in a position to win a game. That's what you respect about the guy."

In the wake of Jimenez's struggles, youngsters such as Jhoulys Chacin and Juan Nicasio have stepped up to keep the Rockies in the thick of the NL West race. That's been even more vital since Jorge De La Rosa went out with a season-ending elbow injury.

Chacin has compiled an 8-4 record with a 2.81 ERA — numbers definitely worthy of All-Star consideration.

And Nicasio, called up from Double-A Tulsa in late May, is 2-1 with a 3.38 ERA.

Now if only Jimenez could get on track.

To facilitate that, the Rockies are trying everything. Tracy has started Jose Morales at catcher over Chris Iannetta in each of Jimenez's last three starts. Morales and Jimenez have developed quite a bond, but Jimenez quickly asserts he's equally at ease with Iannetta calling the pitches.

"I don't want to make anybody feel bad," Jimenez said.

Morales has certainly been impressed with what he's seen from Jimenez.

"We all know he's one of the best of the best," Morales said. "When he's on, it's unbelievable. When he's throwing all five pitches for a strike, and where he wants them, teams don't have a chance."

That's where Jimenez was early last season, and where he's striving to get back to now. He thinks he's close and remains upbeat.

"Things are going to change," Jimenez said. "They have to change."


Pat Graham can be reached at http://twitter.com/pgraham34