Frank Seiler Butterworth, Sr. (September 21, – August 21, 1950) was an American football player and coach. Butterworth attended Yale University where he was a fullback on Yale's football teams and a member of the Skull and Bones Society. He was famously enucleated by Bert Waters during "The Bloodbath in Hampden Park". He was selected as an All-American in and Butterworth was also a track star and boxer at Yale. After his college career was over, Butterworth coached football at the University of California, Berkeley (1895–1896) and Yale (1897–1898). The Yale football team coached by Butterworth went undefeated with two ties, to Army and Harvard.