He struggled during his college career, being injured as a sophomore and was out of school for scholastic reasons as a junior.
[1] His rookie season came until 1961, where he made his professional debut at defensive tackle in the twelfth game against the San Francisco 49ers, replacing an injured Joe Lewis.
[2] He was a backup at right defensive tackle behind Billy Ray Smith Sr. and Fred Miller.
[4] He was released on September 24, to make room to activate Pete Gent from the taxi squad.
[7] Diehl was a player-coach for the Harrisburg Colts in the semi-professional Atlantic Coast Football League.