He established himself as a ball hawk by intercepting five passes and recovering six opponents ' fumbles , and he was also credited unofficially with having forced six fumbles .
Succeeding Hall of Famer Bill George at middle linebacker , Butkus made an immediate impact as a rookie .
Butkus established himself as a ball hawk by intercepting five passes and recovering six opponents ' fumbles , and Butkus was also credited unofficially with having forced six fumbles .
Succeeding Hall of Famer Bill George at middle linebacker , Butkus made an immediate impact as a rookie .