Which running back became the first to rush for 2,000 yards in a season, in 1973?

Which player holds the NFL record for most career receiving yards? Which player holds the NFL record for most career touchdowns? Which running back set the NFL single-season rushing record with 2,105 yards in 1984? Which quarterback set the single-season records with 5,477 passing yards and 55 touchdown passes in 2013? Which player holds the official NFL record for career sacks, with 200? Which running back rushed for 2,097 yards in 2012, just after recovering from a torn ACL? Which running back rushed for 2,053 yards in 1997 and retired suddenly in 1999? Which player set the single-season record for touchdowns with 31 in 2006?