With Braun now on the disabled list, the Brewers will try to snap a five-game skid to their NL Central rivals and avoid losing for a 10th time in 11 games in Cincinnati on Saturday.
Milwaukee (27-39) is batting .305 and has scored 41 runs while winning five of seven games. Braun was out with a sore right thumb in the last four of those contests, and the slugger was placed on the DL after Friday's series opener.
"This is a move we tried to avoid," manager Ron Roenicke said. "After talking to him, I think this is the right way to go."
The Brewers had 12 hits Friday but suffered a 4-3 loss in 10 innings. Jay Bruce's game-ending home run gave the Reds their fourth win in five contests.
"I told somebody earlier it never gets old," said Bruce, who is tied for the team lead with 11 homers. "I hit homers, but walkoffs are completely different. They're a little sweeter, especially this one because of (Thursday's 6-5 loss in 14 innings to the Chicago Cubs)."
Homer Bailey (4-4, 3.47 ERA) will try to help Cincinnati (41-27) keep rolling by building on one of his best starts of the season. He gave up one unearned run over eight innings and struck out eight in a 6-2 win over the Cubs on Monday.
"I just wanted to be aggressive and try to be very efficient," Bailey said.
Bailey is 3-0 with a 1.70 ERA in his last five games against NL opponents but is 1-5 with a 5.81 ERA in 11 career starts versus Milwaukee. The right-hander, though, gave up one run over eight innings and struck out 10 in his most recent matchup, a 3-1 home win July 20.
Like his counterpart for Saturday, Yovani Gallardo (5-6, 4.74) will also seek to build on a superb outing. He tossed eight scoreless innings in a 6-1 victory in Miami on Monday after going 1-5 with a 6.21 ERA in his previous seven starts.
Gallardo struck out four to became the third Brewer with 1,000 strikeouts, joining Teddy Higuera and Ben Sheets.
"Getting 1,000 strikeouts, it's a big number," Gallardo said. "It's definitely a lot of work. It's a lot of pitches thrown. It's one of the goals and hopefully keep moving forward to get to the next one."
Gallardo struggled in his lone start of the season against the Reds, allowing three runs, five hits and five walks in four innings of a 4-3 road loss on May 10. He has a 5.17 ERA in losing his last three starts at Great American Ball Park.
Bruce, hitting .387 in his last seven games, is batting .419 (13 for 31) with two home runs versus Gallardo. That's the second-highest average of the 15 hitters who have faced the right-hander 30 or more times.
Rickie Weeks has the best average against Bailey of any hitter who has faced him at least 20 times, going 11 for 24 (.458) with a pair of homers.
The Reds won't have reliever Jonathan Broxton available, as he was placed on the 15-day disabled list Saturday with a sore pitching elbow. Cincinnati called up right-hander Pedro Villarreal to take his roster spot.