Stackhouse is expected to sign sometime in the coming days, a person with knowledge of the deal told The Associated Press. The person spoke on the condition of anonymity because the contract hasn't been finalized pending a physical.
The deal was earlier reported by ESPN.com and the Milwaukee Journal-Sentinel.
The Bucks are in need of a scoring threat after guard Michael Redd tore ligaments in his left knee last Sunday and will miss the rest of the year.
Stackhouse, a 14-year veteran, was part of a four-team, eight-player trade in the offseason and became an unrestricted free agent this summer, when the Memphis Grizzlies bought out his contract for $2 million.