PHOENIX -- Grant Balfour wasn't necessarily expecting the news to come the way it did, but he was more than happy to hear it.

As Balfour was exiting the mound in the A's win over the D-backs on Sunday, Oakland manager Bob Melvin congratulated him for a good outing, took the ball and gave him a quick oh-by-the-way whisper.

"He just said, 'I'm going to go with you as the closer,'" Balfour said Monday morning.

Balfour, who has eight years of Major League service time but has never been a full-time closer, made no secret about the fact that he wanted the job heading into Spring Training. He is coming off two stellar seasons in a setup role, having put up a 2.47 ERA and 1.032 WHIP in 62 appearances last year with Oakland and a 2.28 ERA and 1.084 WHIP with Tampa Bay in 2010.

Balfour, 34, was spectacular in 2008 for Tampa Bay, striking out 82 batters in 58 1/3 innings and pitching to a 1.54 ERA for a team that went all the way to the World Series.

He's amassed 10 saves as a fill-in closer over the course of his career, but he said he's eager to start tallying a lot more.

"I was happy to hear it," Balfour said. "You don't want to get too excited and lose track of what you've got to do. ... I've just got to keep doing what I've been doing."

Balfour, a right-hander, had been in competition for the role with veteran left-hander Brian Fuentes, who has saved more than 20 games in seven separate seasons, including an American League-leading 48 when he was with the Angels in 2009. Fuentes saved 12 games last year with a 3.70 ERA, but he was a replacement for injured closer Andrew Bailey, who has since been traded to Boston.

So far this spring, neither Balfour nor Fuentes had been particularly impressive from a numbers standpoint. Heading into Tuesday's game, Balfour had a 7.94 Cactus League ERA and Fuentes' was 7.50. Then again, Balfour has been pitching better of late. He was touched up for five runs in 1 2/3 innings in his first two outings, but since then he's been unscored upon in four innings over four appearances.

"The last four or five outings, it's been good," Balfour said. "I've been throwing up some zeros and I just want to continue to take that into the season. I'm starting to feel good and I'm excited about the season and I'm excited about what we've done here in the spring as a team. It's been great. So it's another part of the puzzle, and I want to pull my weight and do my job. Hopefully everyone can do their jobs and we'll be good."

That sounded good to Melvin, who said he picked Balfour primarily because of his dominance in the setup role last year. Melvin didn't foresee any issues with Balfour taking what, by all counts, is a super-intense mound demeanor and transferring it to the ninth inning.

"If you're profiling the demeanor of a closer, you would find a picture of Grant Balfour right there," Melvin said. "Now, the uncertainty is that he hasn't done it before, but he's excited about doing it, he wants to do it, he came into camp with the mindset that he wanted to do that, and therefore that's the direction we're going."

Balfour admitted that he brought the goal of becoming the team's closer into camp, and he even vocalized that wish to the coaching staff, but he said he had no plan to alter his approach now that he's tasked with getting the last three outs of games.

"My mindset's going to say the same, and that is going out there and throwing up a zero," he said. "No one wants to give up runs, no matter whether you pitch in the first or second or whatever inning you're pitching. You want to go after hitters, you want to be aggressive and I don't see anything changing."

Fuentes, meanwhile, said he wouldn't change anything in his routine either.

"You still have to go out there and get guys out," Fuentes said. "And now it'll be the seventh and eighth innings instead of the ninth. I'd take [the closer's demeanor] in the fifth inning if I had to. That's just the way it is."

Fuentes said he was disappointed that he lost the closer competition but that he'd be ready to take on the setup role he'll now be slotted into.

"I wish I could have thrown better in spring to give myself a better opportunity," Fuentes said. "Ultimately I understand that regardless of how well I threw, it might have ended up the same way. But I believe I'm very capable of doing it. Unfortunately it wasn't the opinion of those in command."

For now, Fuentes will root on Balfour. The two get along, and Fuentes said he believes Balfour can succeed as the team's closer.

"He has the stuff, that's for sure," Fuentes said. "Everybody who's watched him do it for the last four or five years, the way he's pitched has been at a high level and very effective. And I'll be there to help him if he needs help, or talk about it or whatever. But I think he can do it."