CHICAGO -- Rookie Tyler Colvin forced his way onto the Cubs' Opening Day roster with a great spring. And in the first month of the season, the versatility that made him an attractive option coming out of Arizona has been on display.

Playing all three outfield positions, Colvin has shown solid defense along with great speed and nice pop at the plate. And he's even improved his plate discipline that was one of the few knocks on him at the start of the season.

With the Cubs trailing, 3-1, in the bottom of the ninth on Tuesday night, manager Lou Piniella showed confidence in his 24-year-old slugger, pinch-hitting Colvin as the potential tying run with two outs.

And even though Colvin struck out against Nationals closer Matt Capps to end the game, Colvin relished the chance to produce with the game on the line and appreciated the manager's trust.

"I hope to get some more at-bats like that in the future," Colvin said. "It shows his confidence in me that I could get it done in that situation."

It wasn't an easy task for Colvin, who got to sit on the bench for nine innings on a chilly evening, only to face a pitcher throwing a mid-90s fastball.

"I like to come up in situations like that," Colvin said. "It is tough coming off the bench in cold games like that. We can come in [the clubhouse], get loose and get warm, get a little sweat going before we go out there so we're ready to go."

"Colvin has held his own pretty well here," Piniella said. "If Colvin were playing on other teams, he'd be an everyday outfielder right now the way he's performed."

Colvin is part of a five-outfielder rotation, and while Piniella admits it's a challenge to distribute playing time, it's a nice problem to have.

"I've got some good outfielders," Piniella said, "and it's not easy for me to play five of them. But that's what we have, and I'm trying to do the best that I can with it."

Colvin earned his eighth start of the season Wednesday afternoon against the Nationals, spelling Alfonso Soriano in left field.

Piniella: Big Z gives us 'presence' in 'pen

CHICAGO -- The move of Carlos Zambrano from the rotation to the bullpen has been the source of many questions for Cubs skipper Lou Piniella over the past week.

A reporter asked the manager how Zambrano might handle not pitching in the "limelight" as a starter or closer.

"The limelight is winning baseball games," Piniella said. "That's what the limelight is. The seventh- and eighth-inning roles are very important. [Carlos] Marmol did that well here for a few years.

"The way the game is played today, most of the games are decided late. You better hold the opposition down in those three innings -- seventh, eighth and ninth -- because, if not, you're chances of winning aren't very good.

"Zambrano gives us a presence. He gives us experience. He gives us a good situation. He gives us the opportunity to win baseball games."

Cubs yet to produce consistent offense

CHICAGO -- Entering Wednesday, Cubs starters had the third-lowest ERA (2.99) in the National League, and the staff has posted a 2.05 ERA over the past 10 games. Yet, the team has squandered many quality starts -- like Tom Gorzelanny's effort Tuesday -- with the inability to produce consistent offense.

"We've had eight games already where we've scored two runs or less and we've lost them all," Cubs manager Lou Piniella said. "That's something we've got to get better at. It's very, very difficult to win when you don't score runs.

"Usually, when you see teams win with a lot of consistency, you're talking about five or more runs. Our offense should continue to get better as the weather warms up, as they start to get more at-bats. I have every confidence that it will. The sooner that we do, the more consistently that we'll win."