The two-year deal has a team option in the second year, sources told ESPN's Ian Begley. The terms of the deal were first reported by 98.7 FM Arizona Sports.
The 2011 Naismith College Player of the Year at BYU, Fredette played the past three seasons in the Chinese Basketball Association. In November, he scored 75 points for the Shanghai Sharks in a loss to Beikong.
The Suns will be the fifth NBA stop for Fredette, who last played for the New York Knicks during the 2015-16 season.
In five NBA seasons, Fredette has averaged 6.0 points and 1.4 assists per game.