After being drafted in the fourteenth round of the 1958 NFL draft by the New York Giants, Roberts opted instead to sign with the Toronto Argonauts of the "Big Four" (soon to be renamed the Eastern Conference) of the Canadian Football League, whose head coach was fellow Californian Hamp Pool. Forming what the Canadian Press called "the best all-round backfield in the Big Four" along with Dick Shatto and fellow rookie Dave Mann, Roberts rushed for 595 yards and five touchdowns, including touchdown runs of 67 and 85 yards.
After being selected in the fourteenth round of the 1958 NFL draft by the New York Giants, Roberts chose to join the Toronto Argonauts of the "Big Four" (soon to be renamed the Eastern Conference) of the Canadian Football League, whose head coach was fellow Californian Hamp Pool. Along with Dick Shatto and rookie Dave Mann, forming a well-rounded backfield, Roberts rushed for 595 yards and five touchdowns, including touchdown runs of 67 and 85 yards.