PHOENIX -- Coming out of Spring Training, it was assumed the Diamondbacks' hitting attack would be the team's strength and the pitching would be its Achilles' heel.

It's far too early in the season to draw any conclusions but through the first week of the season, the Diamondbacks certainly are thrilled with the way their pitchers have performed.

Arizona entered Tuesday's home opener with the Rockies wielding a National League best ERA at 2.68.

"It's been unbelievable," D-Backs manager Bob Melvin said. "We've gotten good starts from every one of our starters, and the bullpen has come up big for us. So if those were the question marks coming out of Spring Training, obviously we're off to a good start."

The starters have set the tone, and the relievers have followed suit.

"If we finished the year at a 2.60 ERA, I'd probably be surprised," Melvin said. "But certainly, that was something that everyone was kind of looking at to be our Achilles' heel right away. And so far, six games into the season, we feel pretty good about where our pitching is."

In contrast, the offense has scuffled a bit with runners in scoring position and was 11th in the league in runs scored heading into Tuesday.

No worries: Third baseman Chad Tracy is 0-for-8 since going 3-for-4 in the D-Backs' final game in Colorado and was hitting .190 heading into Tuesday's game. He was held out of Saturday's game with some soreness in his groin.

"He's swung the bat fine," Melvin said. "We sat him out for a game because of a little bit of a groin and leg issue, but I'm not concerned about him. He's had a big game already, and he's in the three hole for a reason. We don't worry about him."

Lineup notes: Jeff DaVanon got the start in center on Tuesday over Eric Byrnes, while Conor Jackson remained at first instead of Tony Clark.

Melvin said he wanted to get DaVanon, a switch-hitter, in there against Colorado right-hander Aaron Cook. It was DaVanon's fourth start of the year.

"He gives us a lot of versatility, especially against good righties that are tough on right-handed [hitters]," Melvin said. "Byrnes is more of our everyday center-field guy, but against [Cook], we just felt like he profiled a little better for left-handed hitters."

That line of thinking didn't apply when it came to keeping the right-handed-hitting Jackson in the lineup instead of the switch-hitting Clark. Last time they faced Cook, Melvin played Clark and, in fact, started an entire lineup that either hit from the left side or switch-hit. Cook held that lineup to three runs over seven innings.

"I think maybe last time we showed [Cook] eight left-handed hitters, which doesn't really make him make adjustments," Melvin said. "I think if we have another righty in the lineup, now he has to go to the other side of the plate and do some things a little bit differently. I think we made things a little too easy for him with all left-handed hitters last time."

Ring bearer: White Sox executive Roland Hemond presented Arizona reliever Luis Vizcaino with his 2005 World Series ring in a ceremony inside the Diamondbacks clubhouse. "It was nice of [Melvin] to let me do that," Hemond said. "It went very well."

Memories: Prior to Tuesday's game, Melvin was asked for his most memorable Opening Day moment.

"I caught [then vice president] Dan Quayle's first pitch in Baltimore, and he wanted me to get down, and I wouldn't do it," Melvin said. "I didn't want to embarrass myself and not catch it, so there was a little bit of an issue there that stalled things for a bit."

In case you're wondering the pitch was slightly off to the right.

Up next: The Diamondbacks and Rockies continue their three-game set on Wednesday night with a rematch of last Thursday's pitchers. Right-hander Miguel Batista will go for his second win this year against the Rockies, while lefty Jeff Francis will try to avoid a repeat of his five run, 4 1/3-inning performance.