The former Liverpool and Blackburn defender joined the Latics on trial last week after being released by Celtic and has impressed manager Paul Jewell enough to be offered a deal.
The 30-year-old will become Jewell's fourth signing of the summer after Rotherham goalkeeper Mike Pollitt and defenders Pascal Chimbonda and Ryan Taylor from Bastia and Tranmere respectively.
Henchoz joined Celtic last season after failing to win a place in Rafael Benitez's first team at Liverpool.
He had been a key member of the side under previous boss Gerard Houllier and starred in the 2001 cup treble success.
Henchoz first came to England when he joined Blackburn from Hamburg in 1997. He moved to Liverpool in a £3.5million deal two years later.Reuse content