Rivera accepted the assignment and will report to Minor League camp beginning Thursday. The Brewers are expected to release Balfour later this week, but will try to re-sign him for less than his current $415,000 price tag. Balfour said he would take a few days to decide whether to accept.
Rivera will join JD Closser at Triple-A Nashville. Rivera was hitting .425 in Spring Training games entering Tuesday, Closser .360, and the Brewers had serious concerns about losing one or both on the waiver wire.
"Given the state of catching, I would have thought somebody would have taken a shot," assistant general manager Gord Ash said.
Rivera's agent spoke with several teams, including the White Sox, who lost catcher Toby Hall to a potentially season-ending shoulder injury Sunday, but could not find a better situation than the one Rivera faces with Milwaukee. The team traded for Johnny Estrada in November, shifting veteran Damian Miller to a backup role. Miller battled a myriad of injuries last season, and Rivera started the team's final 10 games.
"I'm not going to take a chance and go somewhere else at this stage of spring and try to learn another organization," Rivera said. "That's why I decided to stay here. I'll go to Nashville and do my job."
Brewers manager Ned Yost likes the team's catching depth, a major area of weakness in the organization in recent seasons.
"On the selfish side, I feel good for our organization that we've got those two guys down there," Yost said. "I feel bad for them, because they've both had good springs and you want all of your guys to play in the big leagues.
"But, if something happens, we're not going to have to scramble."
The contract Balfour signed with Milwaukee guaranteed him $415,000 even if he pitched in the Minor Leagues. The club was not willing to spend that much, so they will pay him 45 days' termination pay (just over $100,000) and on Tuesday afternoon were expected to place the 29-year-old on release waivers. The team could then re-sign him to a lesser deal later this week.
Balfour was 0-2 with a 11.25 ERA in eight spring appearances. He missed all of 2005 and most of 2006 after undergoing Tommy John elbow ligament replacement surgery.
"I don't know what's going to happen yet," Balfour said.
25th man: Rivera's departure means the final roster spot will come down to utility man Vinny Rottino or outfielder Tony Gwynn Jr., Yost said.
Rottino provides defensive versatility, essentially serving as an extra outfielder, infielder and catcher all in one. Gwynn provides offensive options because he can pinch-run, he can pinch-hit leading off an inning "when you really need a catalyst guy," Yost said, and he is a superior bunter.
"You just decide what you need most," Yost said. "Do you need the defense or do you need the offense? How many times are you going to need the defense over that offense? How many times are we going to need to pinch-run for [Damian] Miller or [Johnny] Estrada in the eighth or ninth inning of a ballgame? ...
"Or, you go with the best of both worlds and you take 11 pitchers and you keep them both," Yost said. "You can sit here and make a case for all three scenarios."
On the pitching side, the team is leaning toward keeping seven relievers to go with its five starters. Francisco Cordero, Derrick Turnbow, Matt Wise, Brian Shouse, Carlos Villanueva and Elmer Dessens appear set for the bullpen, leaving Greg Aquino, Jose Capellan, Chris Spurling and Joe Thatcher in consideration for one spot. Aquino and Capellan each have a Minor League option remaining, and Spurling and Thatcher, both of whom pitched poorly in Tuesday's loss to the A's, are in camp on Minor League deals.
Done deal: The Brewers found a taker for right-hander Ben Hendrickson on Tuesday, trading the former top pitching prospect to the Royals for catcher Maxim St. Pierre.
St. Pierre, a native of Quebec City who turns 27 on April 17, batted .202 in 78 games for Triple-A Toledo last season. He spent the first 10 years of his career in the Tigers organization and is expected to go to Double-A Huntsville.
Hendrickson, 26, is 54-48 with a 3.41 ERA in the Minors over the last seven seasons but went 1-10 with a 7.41 ERA in stints with the Brewers in 2004 and 2006. He cleared waivers and was sent outright to Nashville on March 18, but Melvin said the Brewers would pursue a change of scenery.
Injury notes: Third baseman Corey Koskie was unable to make significant progress with his post-concussion syndrome and has been sent home to Manitoba, Ash said.
"He's going to get into a non-baseball-related environment," Ash said. "We'll see if that helps him."
Koskie suffered a concussion last July 5 and did not play the rest of the season. He has seen a variety of specialists but continues to experience symptoms when he tries to elevate his heart rate.
"He wants to be a part of this so bad, and it's just hard for him being down here," Yost said. "He pushes himself through things, and when you do that with this type of thing and you get set back, you don't get back to where you were tomorrow. He was pushing himself a little too hard."
Third baseman Tony Graffanino sat out Tuesday with back spasms. He started feeling tight Monday morning and said it only got worse during the bus ride to Tucson, where the Brewers played the Diamondbacks. Graffanino left the game after the second inning but said he felt much better Tuesday.
Ash also said outfielder Laynce Nix (strained oblique) would stay behind in extended Spring Training and would start the year on the disabled list.
Last call: Dave Bush started Tuesday's 8-3 loss to Oakland and surrendered three runs, two of them earned, on six hits in five innings. "I thought Bushie had a really, really good day for having such a bad game," Yost said with a chuckle. "That means that it could have been so much worse. His command was way off and he threw 30-some pitches in the first inning, but he kept us in the game. He had a great, bad day." ... Outfielder Brady Clark stopped by Maryvale Baseball Park on Tuesday to say some goodbyes. The Brewers traded Clark to the Dodgers on Monday for right-hander Dessens, who arrived at Maryvale at about 12:45 p.m. CT. ... The Brewers have only 35 players on their 40-man roster. ... Ben Sheets will make his final tuneup for Opening Day when the Brewers face the Giants at Scottsdale Stadium on Wednesday. Left-hander Noah Lowry will start for San Francisco.
Adam McCalvy is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.