MILWAUKEE -- A 13-6 loss to one of baseball's weakest offenses was the final straw for Brewers general manager Doug Melvin, who answered Tuesday's blowout loss to the Padres with a flurry of personnel moves on Wednesday morning.

Melvin sent the Brewers' three longest-tenured on-field employees packing. He dismissed pitching coach Bill Castro, designated infielder/outfielder Bill Hall for assignment and optioned shortstop J.J. Hardy to Triple-A Nashville. Chris Bosio was promoted from his post at Nashville to serve as the team's interim pitching coach, and outfielder Jason Bourgeois and shortstop Alcides Escobar -- considered by some to be Milwaukee's top prospect -- followed as replacements for Hall and Hardy.

The shake-up was designed, according to Melvin, "to try to get the club jump-started."

"You're afraid of this, but it happens sometimes," Melvin said. "We lost CC Sabathia, we lost Ben Sheets [to free agency]. We knew we had to play well. But I get the impression that we're 20 games under .500. We're not. We're two games under .500. We're like the Chicago White Sox, who just spent $120 million [on recent pick-ups Jake Peavy and Alex Rios] to improve their ballclub. [Sox GM] Kenny Williams will never give up on his ballclub, and I'm not giving up with mine.

"That's why we make moves. We don't want to give up. We don't want to lose."

They lost big on Tuesday, when Brewers pitchers combined to surrender a season-high 22 hits to a Padres club that, even with that outburst, ranked last in the National League in batting average, runs scored and slugging percentage. Since the Brewers' chief National League Central competitors also lost Tuesday, third-place Milwaukee remained 6 1/2 games behind division-leading St. Louis and 3 1/2 games behind second-place Chicago.

Melvin met with Castro after the game -- the Brewers' 22nd loss in their past 35 games -- and let him go.

In Castro's place is Bosio, 46, who was the Tampa Bay Rays' pitching coach in 2003. He was in his first season as pitching coach at Triple-A Nashville, a staff that entered Wednesday tied for second in the Pacific Coast League in team ERA (4.05) while allowing the fourth-fewest home runs (83). 

"It's tough, but I have a job to do," Bosio said of replacing Castro. "I'm going to do everything I can to help the club win. ... It will be a learning experience for me, too, but I'll be applying stuff as we go. I'm not here just to watch."

Bosio also pitched in Milwaukee, and his final year with the big league club was Castro's first as a member of the coaching staff.

But Castro's tenure with the Brewers went back much further. He pitched in the organization from 1970-80, then returned to the club as a Minor League coach from 1988-91 before taking a job as the big league bullpen coach. He served under six different managers from 1992-2008 before incoming manager Ken Macha, on Melvin's advice, retained Castro as his pitching coach for 2009. The idea was to retain some consistency in the organization.

Losing Sabathia and Sheets over the winter hurt Castro's cause, and so did losing Dave Bush, Seth McClung and Jeff Suppan to injuries beginning in June. Through Tuesday, the Brewers' pitching staff ranked 27th in the Major Leagues with a 4.84 ERA while allowing a Major League-leading 151 home runs in 112 games. The staff also issued 421 walks, fifth-most in the Majors.

"It just so happens that the pitchers who were here last year haven't performed as well,' Melvin said. "Their ERAs are a run or a run and a half different. We have 50 games left and we have to turn that around."

When Melvin told Macha about his decision to relieve Castro on Tuesday night, the skipper appeared "shocked," Melvin said. Macha, in turn, passed the news on to his other coaches, who were equally surprised.

"They didn't realize the situation had become that critical," Macha said.

Castro was disappointed, but not shocked. He spent the day fielding calls from well-wishers, and by the time players were trotting off the field after batting practice, Castro was out on his backyard deck with his family, tending to some chicken on the grill.

"I know Doug feels bad, and I feel worse," Castro said. "I don't have any regrets. I did the best I could with what I had. The worst thing was losing Bush and Suppan, because that had a domino effect."

He would be open to remaining in the organization as an instructor, and said Melvin suggested meeting for lunch in the coming days. Castro expressed no regret about leaving the relative security of his bullpen post for the spotlight that accompanies a Major League pitching coach.

"I always wanted to be a big league pitching coach, and it was especially special that it happened for me in Milwaukee," he said. "This is the only organization that I've known, basically. Everything I have done in baseball is thanks to the Brewers. But they had a make a change, and I was the guy."

He was not the only guy.

Hardy and Hall took a bullet for the Brewers' offensive failures. Hardy was hitting .229 and will report to Nashville by Friday. Hall was hitting .201 and the Brewers have 10 days to trade him or release him. A trade will be difficult given Hall's contract. He is making $6.8 million this year, is due $8.4 million in 2010 and has a club option for 2011 that calls for a $500,000 buyout.

"I guess they feel like they need to make something happen after last night's game and the way things have been going," Hardy said. "You can't blame them. They needed to do something. Look what happened last year," when the Brewers fired manager Ned Yost with only 12 regular-season games remaining.

"Maybe they feel like bold moves are going to spark the team. I don't know."

Melvin told Macha he wants the homer-happy Brewers to be more aggressive offensively, and the additions of Escobar (.298 average, 42 stolen bases at Nashville) and Bourgeois (.316 average, 36 steals) should help.

Macha is not a "team meeting" kind of guy, and other than a separate sit-down with center fielder and clubhouse sage Mike Cameron, he stuck with that philosophy on Wednesday. Players didn't need a meeting to learn about the moves, and they watched on live television Wednesday afternoon as Melvin and then Macha explained their reasoning in a press conference.

Macha's own status came up several times during that meeting with reporters. He is only signed through 2010.

"I think we're all evaluated at the end of the year," Melvin said. "From the manager to the general manager, everybody. I don't know why he should feel [nervous]. I talked to him. Maybe I should feel nervous. You never know in this business."