DENVER -- The Rockies rested a couple of their big guns Saturday as manager Jim Tracy tries to find down time for key players near the end of a 16-game stretch without a scheduled off-day.

Carlos Gonzalez was out of the lineup for the middle game of the Cubs series, with Ty Wigginton making his second start of the season in left field, and Todd Helton got the day off, with Jason Giambi spelling him at first base.

"CarGo's had a little bit of a tough time here the last two, three days," manager Jim Tracy said. "He does have some stiffness and soreness, nothing that is out of the ordinary or would be determined to be an injury."

Gonzalez is tied for the team lead in at-bats and games, but he is in a 3-for-24 slump and played through flu symptoms in New York, prompting Tracy to take him out of the lineup Saturday.

"Offensively, obviously he's struggling a little bit," Tracy said. "He's going to get going. When a guy is just getting a little something here and a little something there, where you know there's a lot more in there than what you've seen, this is probably a great time to get him away from it and let him catch his breath and then start back over again tomorrow."

Helton is on a roll, going 5-for-9 his last two games and posting a .364 average through 11 games, but with a night game Saturday and a day game Sunday, he figured to get one of those days off.

"Todd will be back tomorrow," Tracy said. "He has terrific history with Ryan Dempster [the Cubs' Sunday starter]. Todd's swinging the bat very, very reminiscent of a lot of what we saw in 2009. We've just been involved in a doubleheader, we traveled, he played that game; that second day is maybe when it hits an older player a little bit. We backed off of him because of the familiarization of the guy that's pitching against us tomorrow, and we'll plug him back in there tomorrow."

The Rockies have one player who has played every inning of the season, but Cal Ripken doesn't need to look over his shoulder at Troy Tulowitzki, as Tracy indicated he would probably get a day off Sunday, leaving the middle of the lineup well rested for the Giants series.

"To just grind on these guys to the point where you put yourself in a position to potentially break them, I don't want to lay in bed at night and think that that was the case," Tracy said. "I don't feel like I have any 'extra' men. I sit down every day and feel like we have 13 wonderful position players, and what is it that we can do to keep them all involved, to keep them all sharp?

"People need a chance to catch their breath periodically, especially when it's those type of guys that you're going to grind on for 138 or 140 plus games. You got to do it."

Iannetta demonstrating full development

DENVER -- The Rockies went into the season anticipating catcher Chris Iannetta's biggest contributions would come from behind the plate, not at the plate.

His stellar work with the pitching staff has kept the club happy with the decision to depend on him to carry the bulk of the catching load, but there's little to complain about given the way he has shown up offensively.

Iannetta's .219 average is deceptive, with five of his seven hits going for extra bases -- including Friday's three-run triple -- and his .444 on-base percentage is outstanding, reflecting his patience in drawing 11 walks in 11 games. Only Troy Tulowitzki has more, with 14, but four of his are intentional.

"I came in as relaxed as possible," Iannetta said of his new approach in his sixth big league season. "I knew I was going to play. They made that pretty evident. I wanted to get my work in at Spring Training. I had goals of where I wanted to be and the work I wanted to get done that given day, and I used it as a progression instead of trying to get instant results and trying to win a job early."

Far more important, however, is what he has accomplished in working with the pitching staff, as it has established an 11-2 record through the season's first two weeks. His 2.81 catcher's ERA is the lowest in the league, and his calling of Jhoulys Chacin's complete-game shutout Friday exemplifies the confidence the pitchers have in throwing to Iannetta.

"I really trust him," Chacin said after only shaking off a few of 114 signals from Iannetta on Friday. "He's been doing a pretty good job with the pitchers. I just went with him. Whatever he called me, I threw it."

Iannetta is about as grounded as he's ever been, and his self-confidence has been an important foundation in the Rockies' early success. Like many on the team, he is not impressed with the 11-2 record, but rather is focused on how the team can improve from game to game.

"We've had to battle a lot," Iannetta said of his pitching staff. "The credit to the staff that I'd like to give is they've been in situations where they could give up four or five, six runs in an inning, and they've limited it to one or two, and that's given our offense a chance to manufacture runs and a chance to get back in games.

"They're still evolving, they're still working, and they're going to get better."

By all counts, Iannetta's determined efforts at stepping up his own game are paying dividends. He is evolving into a team leader, and he is within eight games of surpassing Jeff Reed in leading the team in games caught, a position where the Rockies have never had a long-term dominant starter.

"Chris has taken the defensive side of his game to another level," manager Jim Tracy said. "Not to say that he wasn't passionate about it before, but I think [it's] the intensity level, with which he's doing his homework, and he's making in-game adjustments, he's recognizing swings in relation to a game plan we put together.

"It may necessitate an adjustment in the middle of an at-bat or the middle of a game, he's just completely on top of everything that's going on back there."

Fate determines Johnson's big league debut

DENVER -- The weather blew Alan Johnson's way when the Rockies were rained out of their second game in New York on Tuesday. After playing a makeup doubleheader Thursday, the Rockies needed a pitcher rested enough to start Sunday's game, and Johnson got the call, setting up his big league debut.

Johnson joined the team in time for the second game of the twin bill and has been on call in the 'pen in case the Rockies needed extra help. Jhoulys Chacin's complete-game shutout Friday kept the bullpen phone from ringing and ensured Johnson's first appearance would be as a starter, the role he's filled for all but five of his 153 Minor League appearances.

"I've always been told, 'Your role in the big leagues will probably be as a reliever of some sort,' but if I can start, that's what I'm going to do," Johnson said. "This is my dream. Growing up, that's what I always wanted to do, and I felt like I was good enough to do it. At any point, starter, reliever, whatever."

The 27-year-old right-hander has made one start in Triple-A Colorado Springs this year, pitching five innings and allowing no earned runs on two hits and a walk while striking out three. The Rockies see him as a flexible enough pitcher to be able to help the club in any number of capacities, and though he was only in Major League camp briefly in Spring Training, he made a lasting impression on manager Jim Tracy.

"He's a very, very competitive guy that will indoctrinate himself to exactly the philosophy that we've been working from since last year, getting after hitters and attacking hitters," Tracy said. "He's got an excellent sinker, and as a result of that, he can pitch off of that with a couple of breaking balls -- his curveball and slider.

"I really think this kid is going to come out here and make a statement for himself, I really do. He's a courageous enough guy. He will not back off, I know that for a fact."

After winning 10 games in each of the last two seasons for Colorado Springs, Johnson said the key for him this spring was to get the release point back from his first couple years of professional baseball. He's known for his control, and the Rockies expect to see him in the zone Sunday.

"I'm obviously not a power pitcher, but I sink the ball and get hitters out front," Johnson said. "I throw offspeed, move it in and out, slow their bats down, speed them up -- go out and pitch. I would love to hit 96 [mph], but that's not me. It never has been really. I've just always been able to locate and make pitches when I need to."

With his parents and some friends coming to town to watch his debut, he knows he'll be excited when he toes the rubber Sunday, but after two years in Colorado Springs, pitching at 1,000 feet higher than Denver's mile high elevation, Johnson is confident he's mentally prepared for the challenge in front of him. And with Ubaldo Jimenez set to return from the disabled list Tuesday, Johnson realizes he's likely heading back down regardless of how well he pitches.

"I've reached my ultimate dream, I guess, so now it's time to cross that off and make another goal," Johnson said. "I'm going to have butterflies. I'm not going to be nervous, but it's more anxious energy. Get out there and prove myself."