Shahrdari Gorgan, headed by Mehran Shahintab, is a favorite to win Iran Super League this season.
Richards, who has most recently played at British club Surrey Scorchers, was a member of Shahrdari Gorgan in 2015-16 season.
The 2.11 power forward has also played in Iranian teams Azad University and Sanat Naft Abadan.
American Parish Perry Petty also plays in Shahrdari Gorgan.