CINCINNATI -- The Reds have more road wins than any team in the Majors. At home, they look about as comfortable as someone sitting on the crunchy plastic that might cover grandma's sofa.

After a 46-minute rain delay to start the game, the Brewers rained runs on ineffective starter Bronson Arroyo on Wednesday night. A 15-3 Reds loss, that included a season-high 20 hits allowed, will be memorable only because shortstop Paul Janish was pressed into service as a mop-up reliever in the ninth inning.

There were no outs in the second inning when Arroyo was pulled after Ryan Braun's grand slam to center field made it a 9-0 game. Arroyo (4-2) tied his season high with nine earned runs allowed on seven hits, three walks and two home runs. He needed 46 pitches to get through the first inning and four batters in the second.

"This game is bizarre," said Arroyo, who saw his ERA climb from 4.91 to 7.15. "The two times I've felt like a monster coming out of the 'pen was this game and the Atlanta game [nine runs allowed on April 25]. I've given up a total of 18 runs in those games. Crazy. In Pittsburgh [on Friday], I felt horrible coming out of the 'pen and put eight zeros on the board. I guess that's why you play the game."

Having just returned from a 3-2 road trip, the Reds own a 10-5 record in the road gray uniforms. They won four of their first five road series. At home, they are only 4-8 and have lost three of four series, dropping the first game each time. The best the Reds can hope for now is a split of the brief two-game series with the Brewers.

"It's like walking into a casino," Arroyo said. "You win one night. It's a horseshoe. It doesn't mean you'll win the next night. It's just the way it is in baseball. We played horrible on the road the last three years here. It just so happens we're playing good now. There's nothing different around."

Cincinnati's pitching staff began Wednesday with the Major Leagues' lowest ERA at 3.61. Their time on that lofty perch did not last long enough to measure for curtains. It was a 3.99 ERA after the loss.

After Rickie Weeks started the game with a double, Arroyo caught a break. With no outs and the heart of the Milwaukee order still due up, Weeks was thrown out at home by right fielder Jay Bruce trying to score on a single.

"I thought I'd roll through that game like nothing," Arroyo said. "But it didn't work out that way. They hit a lot of balls hard."

That was the only positive event Arroyo would enjoy. Following back-to-back one-out walks to Prince Fielder and Mike Cameron, Corey Hart hit a two-run single and J.J. Hardy made it 5-0 with a three-run homer sliced to right field.

"They were off and running," Reds manager Dusty Baker said. "They kept rolling and hitting that ball."

The first three Milwaukee batters reached base on Arroyo in the second inning before a 1-2 hanging breaking ball was launched by Braun over the center-field fence for the grand slam that ended Arroyo's outing.

Baker emerged from the dugout to remove his starter and called on Daniel Herrera. Arroyo left the field amid boos from the 10,982 fans in attendance at at Great American Ball Park.

"With our situation, we were hoping that he would get it in the second inning, because we needed some innings," Baker said of Arroyo. "We played 14 innings and used our whole bullpen two days ago."

Between Arroyo and Herrera, the Reds faced 18 Brewers hitters through the first two innings. The night was reminiscent of Arroyo's June 24, 2008, start at Toronto when he also lasted an inning and gave up 10 earned runs.

"I didn't feel like I threw the ball that bad. They just squared everything up that they hit," Arroyo said.

The Reds twice ended innings with the bases loaded against previously winless Brewers starter Manny Parra (1-4) but finally scored in the fifth. Brandon Phillips hit a two-out solo homer into the left-field upper-deck bleachers. Pinch-hitter Laynce Nix hit a two-out RBI double in the sixth, and in the seventh, Jay Bruce hit his team-leading seventh homer of the season, a solo shot to left field.

Herrera and three more Reds relievers combined to allow only one unearned run through the eighth inning. To save the bullpen, Baker summoned Janish to the mound. Pitching for the first time since he was a shortstop and part-time reliever at Rice University in 2003, Janish struck out his first batter, but gave up five runs. Fielder hit a two-run homer to cap the scoring.

"I was trying not to blow anything out, just run strikes up there," said Janish, the first position player to pitch for the Reds since Lenny Harris on June 1, 1998. "Unfortunately, I had to go through the heart of their lineup."