ST. LOUIS -- Brewers ace Ben Sheets walked around the visitors' clubhouse on Monday like he was ready to go out and pitch. He even wore eye black to make the look more convincing.

But neither Sheets nor the Brewers know when the right-hander will take the mound again. Sheets missed his regular start on Monday, due to a relapse of the vestibular neuritis he suffered briefly last June, and manager Ned Yost was clearly taking a wait-and-see approach.

"I'm definitely not 100 percent," said Sheets, who recently signed a four-year, $38.5 million contract through 2008. "There's still a lot of cobwebs up there."

The 26-year-old was his usual jovial self on Monday, joking around with reporters, but said he was still experiencing balance issues associated with the vestibular neuritis. It is a condition where inner-ear inflammation causes severe dizziness and nausea.

Sheets spent two nights in a Houston hospital while the Brewers took two out of three games in San Francisco, and met up with the team in St. Louis for a three-game series at Busch Stadium.

"We've got him here," Yost said. "There's really not much we can do. We continue him on his medication and he'll see our doctors when we get home."

Yost said Sheets' next scheduled start, which would likely be during the weekend series with Cincinnati, was also in doubt.

"I think that's really going to be a stretch," Yost said. "We have to make sure he's feeling good. We don't want him pushing this thing."

Sheets, who is 1-3 with a 3.95 ERA in four starts this season, was just hoping to be ready to go back out and pitch again soon. The right-hander missed just one start last season, then returned to allow one hit over nine innings against the Angels in his next start.

"They said it's a virus and it's going to go away when it wants to go away," Sheets said.

Spivey slumping: Junior Spivey probably didn't mind a night off on Monday. The second baseman, who is batting .211 with three home runs and eight RBIs, was in the midst of an early season slump.

Spivey was 0-for-8 in the final two games in San Francisco, and had just two hits in his last 25 at-bats. Spivey was batting .294 after going 2-for-3 against the Dodgers on April 18.

"He's scuffling a bit," Yost said. "Junior hit some balls right on the nose [Sunday]. He hit a ball hard to center."

Spivey's batting average has dropped to .211, while his on-base percentage has dropped from .345 to .268 since April 18 and his slugging percentage fell from .529 to .408.

"He feels good," Yost said. "It takes time to work through things. He's doing so well defensively right now, when he does get hot, it will be a big boost for us."

Obermueller's start: Even though long reliever Wes Obermueller didn't get to make his start Monday, which was called because of rain, his manager wasn't worried about throwing the right-hander out there.

"I have confidence in Obermueller," Yost said on Monday afternoon. "I've seen Obermueller pitch big games. I've seen Obie come in and pick us up when we needed to be picked up."

Obermueller, who was set to make his first start of the season, is 0-0 with a 2.25 ERA this year. In eight innings, he has allowed two runs (both earned) on 12 hits, struck out four batters and walked one.

Brewers sign draft pick: On Monday, the Brewers announced the signing of outfielder Lorenzo Cain, who was the team's 17th-round draft pick in 2004.

Cain, a 6-foot-2, 175-pound right-handed hitter, graduated from Madison County (Fla.) High School last spring and recently completed his first year at Tallahassee Community College.

Cain will report to Phoenix for extended Spring Training.

On the farm: The Triple-A Nashville Sounds (10-8) split a doubleheader with the Iowa Cubs on Sunday, dropping the first game, 5-2, but winning the nightcap, 5-4.

Veteran catcher Pat Borders hit two home runs in the victory, the 41-year-old's first two-homer game at any level since September 2002. Julio Santana picked up his second win in relief after striking out three batters in one inning. Jeff Bennett earned his fourth save, despite allowing a run in the ninth.

On deck: Left-hander Doug Davis will start Tuesday night at Busch Stadium opposite St. Louis Cardinals right-hander Jeff Suppan. Davis is 2-2 with a 4.76 ERA this season, while Suppan is 1-2 with a 3.18 ERA.