Coleman started 18 games at offensive tackle for the Riders last year after spending three seasons with the Edmonton Eskimos (winning a Grey Cup in 2015).
The 6'8", 320 lb product of Mississippi Valley St. will be 32 in June. He was originally signed by the NFL's Arizona Cardinals as an undrafted FA in 2008.
*Shortly after my Twitter report, the Riders officially announced the signing of Coleman. The club reports it's a 1-year deal.