He played only one more season, then did a book of his poems & paintings and went to Hollywood, where he had a number of successful films including playing the Black frat leader in Revenge of the Nerds. He was also in my favorite granfalloon, Star Trek, playing the Maquis leader Cal Hudson in Deep Space Nine.
ETA: In 1968 Joe Namath shocked the football world* by growing a mustache. Casey & Jim Marshall had been wearing them all along, but they didn’t count, perhaps due to lack of contrast.
*Shocking the football world has never required extreme measures. See Kaepernick, Colin.