‘Before going 17-31 as Bills head coach over the past three seasons, Williams was considered a defensive mastermind for the Tennessee Titans. In 2000, the Baltimore Ravens — with Marvin Lewis as their defensive coordinator — set an NFL record for fewest points allowed. However, the Titans were actually the top-ranked defense that season, because of the fewest total yards allowed. Williams — who becomes Washington’s sixth defensive coordinator in six seasons — is known for an aggressive defense that uses various formations.’