HOUSTON -- If things really do happen in threes, there will be a lot of nervous managers fretting about their lineup cards.

First, it was Tampa Bay's Joe Maddon. On Wednesday, it was Houston's Cecil Cooper. What started as an innocent oversight ballooned into an embarrassing gaffe that, luckily for the Astros, didn't cost them a win. They topped the Brewers, 6-4, in a game that began with a rare penalty against the home team.

Cooper made two switches to his batting order prior to the game -- most significantly, flip-flopping Kazuo Matsui and Michael Bourn, with Bourn leading off and Matsui in the two-hole.

The lineup in the dugout showed Bourn leading off, as did the one that was posted in the clubhouse.

But the official lineup card that is exchanged at home plate minutes before the game began showed Matsui in the leadoff spot, with Bourn hitting second.

Brewers manager Ken Macha noticed the mistake. He writes his own lineup card with notes before each game, and was puzzled when Bourn stepped to the plate leading off the game. Quickly, it became clear that Cooper had committed an error.

Bourn singled against Brewers starter Yovani Gallardo to lead off the game, but he was quickly called back. Cooper knew immediately what had happened.

"We have three or four safeguards -- two or three coaches, and myself," Cooper said. "Today, no one checked. We were all at fault, but I take the blame, ultimately, because it's my responsibility."

Cooper said he did not look at the lineup card before he submitted it to the umpires.

"I put it in my pocket tonight without even checking it," he said. "Usually, I check it every day. Today, for some reason, I did not check it."

Macha did, though. The Milwaukee skipper's handwritten lineup card is given to bench coach Willie Randolph, who produces the computer-printed version that goes to the umpires. Macha makes sure to check Randolph's work.

"That's probably the thing that I'm worried most about," Macha said. "I tend to check the thing more than once. Probably more than five times."

Cooper's mistake marked the second time in four days that a manager submitted an incorrect lineup card. On Sunday in Tampa, Rays manager Joe Maddon listed two third basemen, and as a result lost the use of his designated hitter. Pitcher Andy Sonnanstine was forced to bat in the three-hole, and he delivered an RBI double in a Rays win.

Once Cooper's mistake was revealed, he did not move from his seat in the dugout, even as the umpires explained the situation to Cooper and to Bourn.

Bourn was sent back to the plate to hit again. Matsui, per rule 6:07 of the Major League Baseball rule book, was called out. Catcher Jason Kendall was credited with the putout.

Geoff Blum, standing on the top step in the dugout and noticing that Bourn was becoming agitated, called his young teammate over and emphatically explained what had happened.

"Nobody explained it to Michael," Blum said. "He started to get a little heated, he thought he did something wrong. I just wanted to make sure that he knew it wasn't his fault. You try to explain the situation and just calm him down. He's going to have to hit again. That was my main focus, to make sure he knew it had nothing to do with him."

Curiously, it was Blum, and not anyone from the coaching staff, to make sure Bourn kept his cool.

"I'll be honest, yeah, I was a little surprised," Blum said. "I don't know how often it happens over the course of the year, but I've got close to 10 years in. ... I heard about the one in Tampa the other day, and this is the first time I've actually seen it in person. I felt more for Michael -- what he was going through -- and wanted him to know it had nothing to do with him. He shouldn't be frustrated with the umpires or himself."

Meanwhile, Brewers starter Gallardo didn't understand at first what was going on. He played catch with Kendall to stay warm while the umpires sorted it out. Gallardo went on to walk Bourn before Lance Berkman put the Astros on the board with a double, one of six Houston runs against the young Brewers ace.

"I had no idea what was going on," Gallardo said. "It took a little bit to get it all squared off, but today just wasn't a good day for me. It was bad."

Bourn later commended Blum for stepping in and explaining the situation and helping him to stay focused while he made a second plate appearance in the first frame.

"He helped me get through that first at-bat and go on for the rest of the game," Bourn said. "It worked out for us. I walked and Lance ended up hitting a double and I scored. We won the game, that was the most important thing."