In his rookie season he was used as a defensive lineman , before being switched to offensive guard the next year .
Hagen was selected by the Dallas Cowboys in the third round ( 74th overall ) of the 1969 NFL Draft .
In Hagen 's rookie season Hagen was used as a defensive lineman , before being switched to offensive guard the next year .
Hagen was selected by the Dallas Cowboys in the third round ( 74th overall ) of the 1969 NFL Draft .