Simplify the following text for a Grade 9 native English-speaking person.
Original: Albert Alexander `` Ox '' Wistert ( born December 28 , 1920 ) is a former All-Pro American football offensive tackle in the National Football League ( NFL ) for the Philadelphia Eagles .
Simplified: Albert Alexander `` Ox '' Wistert ( born December 28 , 1920 ) is a former All-Pro American football player .