Capuano surrendered six hits in 3 2/3 innings but four of the hits and all of the runs followed critical, two-out errors, first by third baseman Abraham Nunez in the seventh inning and then by first baseman Prince Fielder and second baseman Craig Counsell in the four-run Seattle eighth.
None of the runs affected Capuano's ERA but they did hand him his first Cactus League loss.
"That's baseball," Capuano said. "You just have to keep going out there and getting outs."
Capuano pitched in relief of right-hander Carlos Villanueva, another arm vying for one of three openings in the rotation behind Ben Sheets and Jeff Suppan. Villanueva held Seattle scoreless on two hits in four quality innings, and has surrendered only one run in three Spring Training appearances.
"You're never happy with a game ending like that," said Brewers manager Ned Yost, whose club took a 1-0 lead into the bottom of the seventh inning. "But I am very pleased with the way that both of those guys pitched. It's very encouraging."
Capuano and Villanueva are vying with Dave Bush, Manny Parra and Claudio Vargas for the three openings. A wild card is right-hander Yovani Gallardo, who is rehabbing from knee surgery and faced hitters for the first time Wednesday morning.
The game results don't particularly concern Yost or pitching coach Mike Maddux.
"I don't care about the game," Yost said. "I'm looking at the action on their pitches. I'm being picky right now. You can ask Maddux -- I'm burning his ear off. I'm being really, really picky on certain things because I know how important it is for these guys to not only command their pitches but to try to develop extra pitches and extra bullets that will get them out of jams."
"I was pretty pleased with everything that I threw but I was having a little trouble getting the ball inside to the righties," Capuano said. "That's kind of a bread-and-butter pitch for me. That's one thing that I really want to work on a little bit more."
That's what happened in the seventh inning, when Capuano tried to bury a fastball inside on Mike Morse. The pitch drifted over the plate and Morse hit an RBI double that knotted the game at 1.
"It's obviously getting late in spring and they're evaluating all the time and trying to make decisions," Capuano said. "I think we'll make the decisions for them."