"I don't know if this is a 'backup' or not," Sheets said. "It might be."
It was a disappointing end to an otherwise encouraging session. Sheets pitched to several members of the Brewers' rookie Arizona League affiliate.
"When I was warming up it felt as bad as it's felt in two weeks, but once I got out there it felt great," Sheets said. "That was a good thing, I think. It was at the point where I wasn't thinking about it.
"I think I have more life on my ball now than I did earlier. I don't know why. I was kind of getting there [when he got hurt], but my fastball had really good life today."
Entering Monday, the start of a crucial nine-game, three-city road trip, Brewers starters were 2-10 with a 6.91 ERA over their previous 20 games.
Capuano to 'pen:
With team losses in each of Capuano's last 16 starts and no need for a fifth starter through the end of August, Yost assigned the left-hander to long relief but did not have to replace him in the rotation.
Capuano is 0-10 since May 7, and the Brewers have lost all six of his no-decisions in that span. The 16-start losing streak is a franchise record.
The Brewers built Capuano a 5-0 lead on Sunday, but the Reds rallied to tie the game against Capuano and went ahead against reliever Scott Linebrink. Capuano surrendered two-run home runs to Adam Dunn and Brandon Phillips and lost the lead in the sixth, when he hit Dunn with a pitch, threw two wild pitches and surrendered a sacrifice fly.
"It's more of a mental break than anything else," Yost said. "I didn't think he threw the ball horribly bad [Sunday]. I thought he threw the ball really well. He gave up two two-run homers. He struck out eight, walked one and had four infield hits. He made mistakes to two guys who hit home runs."
The Brewers are off twice in the next 10 days, negating the need for a fifth starter until Sept. 1. If Sheets is ready by then, he could take that spot.
Capuano was expected to be available in relief beginning Monday. He and rookie Manny Parra give the Brewers two left-handed, long-relief options.
"The numbers are there," Capuano said of the losing streak. "I haven't really been getting it done as a starter this year. Hopefully, in the next couple of weeks, I can help out in another way. ... There's no entitlement in this game. Nobody owes you anything."
Capuano has not appeared in relief since his rookie season with Arizona in 2003. He had a 2.84 ERA in four relief stints before moving into the starting rotation and was traded that December to Milwaukee in the package that sent Richie Sexson to the D-Backs.
"I've done it before," Capuano said. "I did it when I first got called up and I was pretty good at it. It's a different adrenaline you get when you hear that phone ringing and they tell you to get ready. I don't think I'll have a hard time adjusting."
He added: "What are you going to do? Put your head down and sulk?"
Outfielder Corey Hart was scratched about 30 minutes before game time with a sore right elbow. He was struck on the elbow by a pitch in the ninth inning of Sunday's loss. Joe Dillon took Hart's spot in the lineup and played left field, with Kevin Mench shifting from left to right field. ... The Brewers have squandered leads of at least five runs five times this season, one shy of the dubious franchise record they set in 1998. ... Including Monday, Yost has employed a different lineup in 11 consecutive games. ... Triple-A Nashville outfielder Laynce Nix was named the Pacific Coast League's batter of the week for Aug. 13-19. The 26-year-old led all league hitters with a .550 batting average (11-for-20) and has homered in his last five games, the longest such streak by a Sounds player since John Wehner established a club record by going deep in six straight from July 1-5, 1999.
Dave Bush (9-9, 5.01 ERA) is scheduled to start Tuesday against Arizona and Livan Hernandez (9-7, 4.86) in a matchup of right-handers.