[1] A full-forward, Blethyn had a slim frame and famously wore glasses on the field.
He made his debut in April 1968 when he was selected on the half-forward flank in place of the injured Alan Noonan.
1972 was a record breaking-year for Blethyn—he finished it with 107 goals and became the first Essendon player since John Coleman in 1950 to kick over 100 in a season.
However, he missed out on the Coleman Medal to Collingwood's Peter McKenna, who kicked 130 goals for the season.
Blethyn left Essendon for good in 1977 when he transferred to SANFL club Port Adelaide.