 Complete the following phrase:  During the 1960s, Zirkle attended Duke University. He began playing football for Duke Blue Devils in 1965, as part of the defensive line. Over the next four years, Zirkle became a major part of the Blue Devils and their success during the 1960s. Playing Defensive tackle, he became the team captain in his senior year in 1968. At the end of his senior year, he was selected to play in the 