SCOTTSDALE, Ariz. -- Ryan Roberts was hoping to make a good impression on new D-backs GM Kevin Towers this spring.

So far, he's done just that. In his first eight at-bats he had six hits and also drew five walks without striking out.

"He's played real well and he's been focused and he's done everything that we've asked," said Towers, who is in his first full season as GM in Arizona. "If I had to pick one guy out that I've been most impressed with, it's been him."

Roberts has played second, third, right and left for the D-backs over the past two seasons. He might wind up adding another position to his repertoire before Spring Training ends as Towers said he'd like to see him play some short.

"I would imagine before the end of the spring he'll probably see some time over there," Towers said. "He's a very valuable guy because he can play everywhere, including the outfield. He's got some power, he's shown me great plate discipline."

After playing well in 2009, when he made the club as a non-roster invitee, Roberts had a poor spring in 2010, was shipped to Triple-A and got just 66 at-bats in the big leagues.

Heilman 'awesome' as he strives for rotation

SCOTTSDALE, Ariz. -- Aaron Heilman is not kidding around when he says he wants to win a job in the starting rotation rather than the bullpen, where he's been for the last five seasons.

The D-backs right-hander tossed another three scoreless innings Wednesday afternoon at Salt River Fields at Talking Stick, giving him five this spring.

"Heilman was awesome," D-backs manager Kirk Gibson said after his split squad's 5-3 win over the Mariners. "He was pounding the zone. He's certainly going for it."

Heilman did not allow a hit and struck out one.

The reason Heilman chose to re-sign with the D-backs during the offseason was the promise that he could compete for a rotation spot. As it stands right now, Heilman, Armando Galarraga, Barry Enright and Zach Duke are battling for the final two spots.

"It's going to be difficult," Heilman said. "We've got a lot of great pitchers here in camp. I knew it was going to be difficult, but I feel like I've got a legitimate shot and that's all I ever ask for. We'll see how everything pans out at the end of this spring, but all you can do is go out there and compete and leave it all out there on the field."

If he does not make the rotation, Heilman could easily slide back into the bullpen, where he has built a reputation as a workhorse. Heilman, whose last start came on May 15, 2005, is the only pitcher in Major League Baseball to appear in at least 70 games in each of the last five seasons.