PHOENIX (AP) -- Brewers manager Ken Macha doesn't like to assign roles for pitchers in his bullpen beyond closer Trevor Hoffman.

But with the all-time saves leader sidelined with a strained oblique in his ribcage, which might force him to miss opening day, Macha may have to use a by-committee approach.

Macha said Thursday afternoon no one has emerged as a leading candidate.

"We'll sort it out. Right now if we have a one-run lead in the ninth inning I'm not sure who we'll call in there," Macha said.

The longtime Padres closer signed a $6 million, one-year deal with the Brewers in the offseason.

Before the extent of the 41-year-old Hoffman's injury was known, reliever Carlos Villanueva said this spring he'd be interested in developing into a closer later in his career.

"It comes with experience," Villanueva said. "The more innings I can have under my belt, experience wise, is going to help. But ultimately, if you're starting, you want to be No. 1 and if you're in the bullpen, you want to be that guy -- setting up or closing games. That's how I see it."

Villanueva made significant strides toward being the eighth inning setup man down the stretch last season. After nine lackluster starts, he moved to the bullpen where he began to excel.

He finished 2-2 with a 2.12 ERA in 38 relief appearances and credits Bill Castro, who was the bullpen coach and is now the pitching coach, for getting him back on track.

"It's a little weird because I was never a reliever (in the minors), but hey, you never know what the calling is," Villanueva said. "When you're a starter, you work on a schedule. You know exactly when you're going to pitch, you know exactly what you have to do between outings. In the bullpen, you've got to be ready every day. There's no excuses, you've got to suck it up and go out there every time they need you."

But Villanueva's spring has been inconsistent, giving up 10 runs over 12 1-3 innings in eight appearances coming into Friday's action. Villanueva has said he'll be happy with whatever role he receives in the bullpen.

"I've done everything. I've gone from long relief to middle relief to late innings. I've finished games. The situations will dictate themselves," he said. "Me being a guy that can go multiple innings, maybe they want to put me in the sixth inning instead. If it's a tie game or extra innings, I just have to be ready for any situation."

Another pitcher who has a role locked up is left-hander Mitch Stetter, who replaces Brian Shouse as the specialist who must get the top left-handed power hitters out. Shouse left for Tampa Bay in free agency this offseason.

While Stetter realizes he'll be throwing against key hitters in certain situations, he doesn't want to limit himself to it.

"I'm trying to concentrate on facing righties and getting right-handers out as well to become more valuable in the bullpen where I can throw a full inning or throw two innings if they need me," he said.

Stetter's best weapon is his deceptive delivery, which hitters have told him looks like it comes from first base or left field. He stands to the far side of the rubber closest to first base and steps across his body to deliver.

"It's a deceptive type of deal, they don't have a real good judgment of where the ball is going to end up, so that helps me out for sure," he said.

Stetter has been strong in 10 spring appearances, allowing just three runs over 11 2-3 innings, but Macha may not want to move his only lefty in the bullpen into a closing role.

Other potential closing candidates could be Jorge Julio (who has 99 career saves), David Riske (22), Todd Coffey (9) or Seth McClung (6).

The closer with the most experience besides Hoffman on the staff isn't in that role anymore. Braden Looper, who has 103 career saves during his time with Florida and the New York Mets, will be relied on as a starter and pitch a significant number of innings.

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AP freelance writer Jonathan Dalton in Phoenix contributed to this report.

(Copyright 2009 by The Associated Press. All Rights Reserved.)