12. MARIO WILLIAMS $25 million
Photograph By David Duprey/AP Images
After six years in Houston, the defensive end signed a six-year, $100 million contract ($50 million guaranteed) with the Bills in 2012, the richest contract in NFL history for a defensive player. Williams also made headlines during the offseason for a different financial transaction: squabbling with his former fiancée over a $785,000 engagement ring.