MILWAUKEE -- The Brewers are prepared to play without injured ace Ben Sheets for at least another four weeks, Brewers general manager Doug Melvin said Tuesday.

Melvin made some waves with that comment at a meeting of the Pen & Mike Club in downtown Milwaukee on Tuesday afternoon. Chiding himself later for the fact that, "I opened my big mouth," Melvin tried to clarify.

"I'm focusing [on being] without Ben Sheets for the next four weeks," Melvin said before the Brewers-Phillies game at Miller Park. "If he's back sooner, then it's a bonus to us. If he's not back in four weeks, then we'll evaluate it at that time. ... We don't know, the doctors don't know, Ben doesn't know right now."

Sheets was shut down last week and placed on the disabled list with right shoulder tendinitis. Once he begins a throwing program, Sheets will have to rebuild his arm strength before going on a Minor League rehabilitation assignment. That process takes time, Melvin said.

"If you want him to come back and throw three innings in the big leagues, he can maybe be back sooner," Melvin said. "But if you want him to come back and throw seven innings, it's going to be longer."

Sheets began the year on the DL while rehabbing an injured muscle behind his right shoulder. He made four starts, then went back on the shelf with the current shoulder ailment. The Brewers are also missing right-hander Tomo Ohka, who has a torn rotator cuff, and Melvin has been scouring the waiver and trade wire for available starters, which tend to be difficult to find.

Last April, Sheets signed the biggest contract in franchise history, a four-year, $38.5 million deal. He missed about 10 weeks in 2005 with an inner-ear condition and a torn muscle behind his shoulder.

"He's not ready today, so it's not really a major concern of mine," Brewers manager Ned Yost said of Sheets' status. "When he gets back, he'll be back."

Ride the hot hand: Bill Hall made his third start of the season in center field on Tuesday, and Yost said he could envision the multi-tasking Hall someday playing the outfield on a regular basis.

"He could be anything he wants," Yost said.

Hall has also started games this season at second base, third base and shortstop. Nineteen of his 31 hits this season, including a game-winning home run on Sunday, have gone for extra bases.

Roster move: The Brewers claimed right-hander Chris Mabeus off waivers from the Oakland A's and optioned him to Triple-A Nashville. To make room on the 40-man roster, the team designated knuckleballer Jared Fernandez for assignment.

Mabeus is a 27-year-old who went 0-1 with a 4.58 ERA in 12 relief appearances at Triple-A Sacramento this season. He has spent his entire six-year professional career in the Athletics' Minor League system, making 210 of his 219 appearances in relief.

According to Melvin, Mabeus was one of the players considered by Milwaukee in the December 2004 trade that sent Keith Ginter to Oakland for reliever Justin Lehr and outfield prospect Nelson Cruz.

"He's a strike-thrower, and he can pitch an inning or two at the back end," Melvin said. But Mabeus will remain at Nashville, barring an injury, because the back end of the Brewers' bullpen "is pretty strong, with [Jose] Capellan and [Dan] Kolb and [Matt] Wise and [Derrick] Turnbow," Melvin said. "That's the area [Mabeus] would pitch in."

The Brewers have 10 days to trade, release or outright Fernandez, who won an Opening Day roster spot with Milwaukee after a strong Spring Training, but posted a 9.95 ERA in four regular-season appearances.

"It's hard to throw a specialty pitch when you're not pitching," said Yost, who attributed Fernandez's struggles to an inconsistent workload.

In limbo? Yost refused to formally name a starting pitcher for Saturday's game against the Twins, an assignment expected to go to Ben Hendrickson. The right-hander has serving as the fifth starter since Ohka and Sheets went down, but has surrendered 10 runs on 11 hits in 7 1/3 innings over his two starts.

"It might be Hendrickson," Yost said. "Why do we have to know who's pitching Saturday, and today's Tuesday? When it gets close, we'll tell you."

With Fernandez out of the picture, the team may be holding back Hendrickson in case he is needed in long relief this week. For his part, Hendrickson was staying positive.

"I threw too many sinkers [on Thursday]," said Hendrickson, referring to his last start in San Diego. "I have to continue with my four-seam command, because when I was using that, even when I was missing, I was missing down. But I got hurt with my two-seamer."

Getting close: Veteran right-hander Rick Helling threw on flat ground Tuesday and is expected to throw off a mound for the first time later this week. Helling has been on the DL since April 16 with a sprained elbow ligament.

On deck: Right-hander Dave Bush is scheduled to start Wednesday night against Phillies right-hander Gavin Floyd. Bush beat the Mets last weekend, snapping a personal three-game losing streak, and has a 1.80 ERA in three home starts this season.