"Potentially an outstanding cornerback. Clark intercepted seven passes in his second year, which is outstanding considering that the Bills have no pass rush. He has started every game since the Bills drafted him in 1976.
Clark could become the Bills' land baron if O.J. leaves any over. He majored in architecture and real estate at Oregon, where he had 13 career interceptions and was the first Pacific 8 freshman ever named National Player of the Week. Clark was born in Pasadena, California, near the Rose Bowl, but never played there for lowly Oregon.
He's a bachelor whose hobbies include music, reupholstering furniture and intimidating quarterbacks."
-Dave Newhouse, The Complete Handbook of Pro Football, 1978 Edition
"A very reliable performer for the Bills, Mario shows improvement in every game. Named to the NFL All-Rookie Team in 1976, he was credited with defensing 18 passes.
Mario was an All-Pacific 8 selection of both AP and UPI at Oregon. He was an honorable mention AP All-America with 13 career interceptions.
Mario's hobbies include reupholstering furniture."
-1978 Topps, No. 57