The 1984 Detroit Lions season was their 55th in the National Football League. The team failed to improve upon their previous season's output of 9âÂÂ7, winning only four games. The team missed the playoffs for the first time in three seasons. Like the previous season, the Lions started 1âÂÂ4, but unlike 1983, the Lions couldn't come back. In a season littered with numerous key injuries, the most painful was star running back Billy Sims suffering a career-ending knee injury in a game against the Minnesota Vikings. In just five seasons in the NFL since joining Detroit in 1980, Sims had set the Lions career rushing mark at 5,106.