Sheets is tentatively scheduled to throw on the side on Saturday.
"Tomorrow [I'm not] worried about; I'm worried about five days from now," Sheets said. "I don't think the extent's that bad. I haven't even been paying attention to it. I don't feel it walking around. There's a couple of positions I get in when I feel it, and one of them is doing the pitching motion.
"It's just like anything; you want to test it. One hour it feels better, then you do something. You just try to leave it alone."
Brewers manager Ned Yost said Sheets' situation will be monitored daily.
"Today's not a day where he's going to throw, so no need to worry about it today," Yost said. "He feels much better right now; we'll just take it and see how he feels tomorrow and go from there."
Sheets, who is 1-2 with a 4.50 ERA in five starts, will continue rest and treatment and hope this setback won't prove to be serious. He was limited to only 17 starts last year because of injury, and has made five trips to the disabled list in the last six years.
"[Pitching only three innings against Chicago] isn't good, but it's better than missing three months like last year," Sheets said.
Sheets, who lives in Dallas and is a native of Baton Rouge, La., took his mind off his injury by visiting relatives in Houston on Thursday.
"I'll hit a couple of Cajun restaurants while I'm here; I'll be ready to go," he said.
Strong starters: Part of the reason for Milwaukee's strong start has been the performance of the starting pitchers.
Brewer starters are 10-5 with a 3.95 ERA and have allowed 27 walks -- the fewest of any team in baseball. The staff's 59 walks are the second-fewest in the National League behind Cincinnati (51) and the fourth-fewest in the Major Leagues behind the Reds, Boston (54) and Seattle (56).
"You try to limit the amount that you beat yourself; you definitely beat yourself by walking guys," Yost said. "There are times where you don't give in and then walks serve a purpose. Our guys have done a great job in that department."
Entering Friday's game, Brewers starting pitchers were 6-0 with a 3.22 ERA in their last 10 games with five quality starts.
"Our command has been off a little bit -- in terms of what we set out to do with a given pitch -- but that's gotten better in the last eight or 10 days. I've been much happier with that," Yost said.
Of course, avoiding walks is nice, but not if your pitchers are throwing too many hittable pitches. Fortunately for the Brewers, they've limited the number of hits along with the free passes.
"When you set forth to deliver a pitch to a certain area, can you command a pitch to that area?" Yost said. "That's what being a successful Major League pitcher's all about. If you can, you're going to be be successsful, if you can't, you're not.
"Neither of them [walks or hits] are good. The only thing that helps you when you're throwing the ball over the plate is they might miss it, they might pop it up, they might hit it at somebody. If you're walking guys, they're not. But you still want to be able to be in a position to command the pitches to put the ball where you want."
Quotable: "I'm happy with the way we're playing, period -- home and on the road -- we're doing fine." -- Yost
Extra bases: Gabe Gross got his fourth start of the season in right field in place of Corey Hart. Both outfielders are 3-for-6 (.500) lifetime vs. Houston starter Roy Oswalt, but Yost decided to go with the left-handed-hitting Gross rather than the right-handed-hitting Hart against the Houston right-hander. ... The Brewers, who were 1-5 against Houston last season, are 54-90 all-time against the Astros and have not won a season series against Houston since winning two of three during the 1997 season. The Brewers are 19-51 all-time in Houston, including 15-39 at Minute Maid Park. "So what?" Yost said. "That doesn't make any difference right now -- that doesn't have anything to do with today." .... First baseman Prince Fielder entered Friday night's game 5-for-16 with three homers, four RBIs and 14 total bases on the road trip.
On deck: Right-hander Dave Bush, who is 3-0 with a 2.43 ERA in five career games against Houston, will try to extend his string of success against the Astros when he matches up against Houston right-hander Chris Sampson in a 6:05 p.m. CT game at Minute Maid Park.