The agreement was first reported by Yahoo! Sports.
The Suns turned to the 6-foot-9, 219-pound Warrick after it became apparent the Amare Stoudemire talks were at a stalemate, reportedly over the length of the deal.
A former first-round draft pick (19th overall), Warrick has averaged 10.1 points and 4.3 rebounds in five NBA seasons, the first four with Memphis. He signed with Chicago and appeared in just 28 games for the Bulls before he was traded to Milwaukee, along with Joe Alexander, for John Salmons.
Warrick appeared in 76 games last season, six as a starter for Milwaukee.
The Associated Press contributed to this report.