Aquino and the Brewers had avoided a potential arbitration hearing when they agreed to a contract that would pay $500,000 in the Major Leagues and $176,000 in the Minors. He split last season between the Brewers and Triple-A Nashville.
"We would have liked to have Aquino in the Minor Leagues, invite him to big league camp and have him fight for a job," Brewers general manager Doug Melvin said. "But at some point, you had to get him through waivers."
The move leaves 39 players on Milwaukee's 40-man roster and leaves the team positioned to add a player via a trade or free agency in the wake of Wednesday's non-tender deadline. Melvin said it's not uncommon for teams to place recently-signed players on waivers, pointing out that 10 of the players nontendered this week already have deals for 2007 including one other Brewer, outfielder Laynce Nix.
Aquino made the Brewers' Opening Day roster, but he soon reported forearm tightness and was sent to Nashville, where he was 3-2 with a 2.53 ERA in 35 games. Aquino was brought back to the Brewers in September and posted a 4.50 ERA in 15 games.
The Brewers originally acquired Aquino in November 2006 along with right-hander Claudio Vargas and catcher Johnny Estrada from the Diamondbacks. Only Vargas, who is eligible for arbitration, remains with Milwaukee.
Adam McCalvy is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.