The Brewers claimed Mabeus on May 16 and was optioned to Triple-A Nashville where he appeared in one game for the Sounds.
"It's my first time in the clubhouse, meeting the guys for the first time, which is great," said Mabeus, who has never made an appearance in the Major Leagues. "I'm looking forward to getting to know everyone and helping out.
I'm excited to be here."
Mabeus began the season at Triple-A Sacramento, where he was 0-1 with a 4.58 ERA in 12 relief appearances. He have up 16 hits and 10 earned runs in 19 2/3 innings and held opponents to a .219 batting average.
Mabeus was selected by Oakland in the 13th round of the 2001 First-Year Player Draft. He had 219 appearances in six seasons in Oakland's system.
Mabeus took the roster spot of right-handed pitcher Chris Demaria, who was optioned to Nashville on Wednesday. Demaria had a 9.53 ERA over his last four games.
Wheeling and dealing: The Brewers acquired right-handed pitcher Jeremi Gonzalez from the Mets for righty reliever Mike Adams on Friday.
Gonzalez was designated for assignment on Thursday and had a 7.71 ERA in three starts for the Mets. He's expected to join the Brewers on Sunday for the final game of a three-game series in Philadelphia.
Gonzalez has a career record of 26-33 with a 4.92 ERA in 110 appearances, including 82 starts.
Adams, who had an 11.57 ERA in two games with the Brewers, was most recently pitching for Nashville.
Role player: Though Rickie Weeks was in the leadoff spot again on Friday, it's still a transitional period for him.
"I'm still getting used to it," Weeks said. "It's a little bit different."
Weeks seems to be adjusting just fine. He has hit leadoff in each of his last 24 starts, hitting .301 (28-for-93) with four home runs and seven RBIs entering Friday's play.
"We can do more up there, plus, we have a little bit of power to start the game," Brewers manager Ned Yost said.
Weeks, who is tied for the National League lead in runs with 36, had a career-high 10-game hitting streak from April 10-22.
Speaking of new roles: Center fielder Brady Clark has been one of the club's hottest players after a very slow start in the leadoff spot this season.
Clark, who hit eighth on Friday, was batting .404 (19-for-47) over his last 16 games, raising his average from .204 to .271. Clark has also hit safely in seven of his last eight games.
"It's just his time," Yost said. "He's made little adjustments here and there."
Injury bug: The Brewers have been forced to shuffle their pitching this season due to a number of injuries, especially to starters Ben Sheets and Rick Helling.
An MRI test on Sheets showed no structural damage to his right shoulder and he may be back by late June at the earliest.
Sheets, who is 1-3 with a 6.64 ERA this season, is continuing a routine of physical therapy and strengthening exercises.
Meanwhile, Helling could be back sooner.
Yost said that Helling is scheduled to throw about 30 pitches off the mound on Saturday.
"We'll see how he feels," Yost said. "He's doing great, no setbacks."
Helling has been out since early April with an elbow injury.
This and that: Relief pitcher Justin Lehr was designated for assignment on Tuesday, cleared waivers and was assigned to Nashville. He will join the team in Des Moines. ... Carlos Lee, who hit his 200th career home run on Wednesday against the Reds, is just 4-for-24 (.174) at Citizens Bank Park before this series. ... The Brewers are 7-20 all-time in Philadelphia entering Friday's game.
Coming up: Dave Bush (3-5, 5.06 ERA) will oppose Philadelphia's Gavin Floyd (4-2, 6.07 ERA) in Saturday's 6:05 p.m. CT game. The Brewers are 4-6 in Bush's 10 starts this season.