Munson, 30, whom the Brewers claimed off waivers on Oct. 15, batted .235 with four homers and 15 RBIs in 50 games for the Houston Astros last season. He hit .283 with seven homers and 26 RBIs for Triple-A Round Rock. He agreed to a one-year, $525,000 deal on Tuesday.
Munson is competing for a backup role on the team behind Jason Kendall, who signed a one-year deal last month. Munson has played parts of eight seasons with Detroit, Tampa Bay and Houston, and has a career .214 average.
Aquino was bothered by tightness in his forearm last season, and pitched for the big league team in April and September. In the final month, he had a 2.84 ERA in seven games. For the season, Aquino was 3-2 with a 2.53 ERA in 35 games at Triple-A Nashville, and appeared in 15 games for the Brewers, posting a 4.50 ERA.
McClung appeared in 40 games for Tampa Bay's Triple-A Durham team, compiling a 1.99 ERA. Milwaukee acquired the right-hander in exchange for Grant Balfour on June 27, and he posted a 3.75 ERA in 14 games for the Brewers.
The team also announced Tuesday it had signed catcher Mike Rivera to a one-year contract, outrighted outfielder Laynce Nix to Triple-A Nashville, and designated pitcher Matt Wise for assignment. Nix was designated for assignment on Dec. 5, and cleared waivers.
Nix, who was hitless in 12 September at-bats for the Brewers last season, batted .268 at Nashville with 24 homers, 20 doubles and 74 RBIs. He was sidelined much of the 2007 season because of a strained right oblique.
Wise was 3-2 with a 4.19 ERA in 56 games for the Brewers, giving up 25 earned runs over 53 2/3 innings. The Brewers now have 10 days to trade Wise, release him or assign him to a Minor League team.
On Monday, the Brewers designated outfielder Kevin Mench for assignment to make room on the 40-man roster for newly acquired reliever Salomon Torres. The moves regarding Nix and Wise clear roster spots for relievers David Riske and Eric Gagne. Gagne was introduced at a news conference Monday night, and at that time, he was given jersey No. 38, which was Wise's number.
Carrie Muskat is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.