Injuries is part of football and any other American sports. Injuries like ACL and double broken legs are career ending which have stopped so many players. 

Robert Edwards tore his ACL, MCL, and PCL in his left knee during a beach football game at the Pro Bowl in 1999. He never fully recovered from that injury. 

Today with a so much improved sports medicine, players now have the opportunity to recover from such injuries like ACL, MCL, and PCL to play competitively.