Bush faced two more than the minimum over six scoreless innings Thursday, then surrendered back-to-back home runs as the Pirates rallied for four runs in the seventh and snapped the Brewers' four-game winning streak, 4-2, at Miller Park.
Pirates starter Tom Gorzelanny (4-1) benefited from some aggressive Brewers baserunning and notched the win after seven innings of work. Salomon Torres earned his ninth save.
"I wish I had the answer for it," said Bush (2-3), who has been beaten by crooked numbers a few times this season. "If I knew why it was happening, I would have fixed it already."
Bush helped his own cause in the third inning, when he doubled off Gorzelanny and later scored on Prince Fielder's two-out single. The Brewers took a 2-0 lead in the sixth, when J.J. Hardy led off with a double, moved to third on Fielder's flyout and scored on a Gorzelanny wild pitch.
But along the way, the Brewers' aggressive baserunning could have cost them some key insurance runs.
They tried what appeared to be a delayed double steal in the third inning -- a ploy that worked in Wednesday's win over the Cardinals -- but Hardy was thrown out at home plate. The play was not what it seemed, Brewers manager Ned Yost said later.
"J.J. took off -- that wasn't a designed play," Yost said. "He wasn't supposed to do that."
Instead, Yost said, it was a straight steal attempt of second base by Fielder, whose two-out single had pushed Hardy to third base. Because there were two outs and cleanup hitter Bill Hall was focused on hitting, he said he did not know Fielder was going to attempt a steal. Fielder stopped halfway between first and second when catcher Ronny Paulino threw down, prompting Hardy to break home.
In the fourth, the Brewers came up empty after a much more conventional decision. With one out and the Pirates' infield playing shallow, Kevin Mench hit a sharp grounder right at the shortstop, and Hall was cut down at the plate.
"If that ball is two steps to the left, I might slide in and be safe," Hall said. "You can't stop running the basepaths hard."
In the fifth, with Tony Graffanino at first base on a single, Yost called for a hit-and-run on the first pitch with his pitcher, Bush, at the plate. Bush first showed bunt, then pulled back to "slash" but Gorzelanny's pitch was out of the strike zone, Bush whiffed and Graffanino was caught dead between the bases.
"Come on, boys, we're trying to win ballgames," Yost told reporters. "We're staying on the attack. We're not scared to try something. It's called aggressive baseball. Bush is one of our best hitting pitchers, it's a bunt situation, we're hoping that he's going to get a fastball he can handle, maybe get first and third. No, it's not walking a thin line."
Did Yost feel like his team ran itself out of the game?
"To be honest with you, yes, we did, but that wasn't the intention," said Yost, who said his only problem was Hardy's break for home in the third inning. "If you're afraid of running yourself out of the game, you might as well go station-to-station and play very safe baseball.
"We're trying to win games. We're going to stay aggressive and we're going to play aggressive."
That was fine with Hall.
"It's been successful for us, so we're not just going to stop it because we had one bad game running the bases," Hall said. "I wouldn't really consider this a bad game, but they made the plays they were supposed to make."
Bush saw his ERA actually drop to 6.03, but he suffered his second straight loss. He has pitched in 38 different innings this season and 29 of them (76 percent) have been scoreless. But in five of the nine innings in which Bush has been scored upon, opponents have tallied three or more runs.
"It's mostly about command," Yost said. "Like tonight, he was cruising along and then made a couple of mistakes that ended up killing him when he didn't have margin for error."
The Pirates took their first lead on the Brewers in three games this season in the seventh. Freddy Sanchez led off with a deep double and scored when Jason Bay blooped a double over Fielder behind first base. Bush retired the next two Pittsburgh batters, then surrendered a two-run home run to Jose Bautista and a solo shot to Paulino in the span of three pitches.
"It's disappointing when you're one pitch away from getting a win or at least putting us in a position to get a win," Bush said. "I'm disappointed in the result, not necessarily with the way I pitched the rest of the game. I'm disappointed that when it came down to it, I couldn't make a pitch when I needed to."
Bush was at 82 pitches entering the seventh inning and has shown no signs of weakness. He believes he is close to turning the corner.
"I don't feel like I'm very far away," Bush said. "Unfortunately, I have not been making my pitches the whole time I have been out there. I have had some situations where I was very close to getting out of a situation and putting together a solid outing. For whatever reason, I'm not quite getting it done."
Adam McCalvy is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.