Low Vig

Mario Williams on Thursday agreed to a six-year deal with the Buffalo Bills that’s potentially worth $100 million and includes $50 million guaranteed, a league source told ESPN NFL Insider Adam Schefter.

It’s the richest deal for a defensive player in NFL history.

The Bills have called a 1:30 p.m. ET news conference to introduce the newest member of their defense, who joins a fearsome defensive line that also includes 2011 first-round pick Marcell Dareus and Pro Bowler Kyle Williams.

Bills players took to Twitter to welcome Mario Williams to the team and celebrate the big addition.

Linebacker Nick Barnett wrote: “Welcome Mario!!! Bills d is not playing games homie!!!”

Receiver Stevie Johnson, who signed an extension earlier this offseason to stay in Buffalo, also hailed the move.

“I Love it! S/O to Them Buffalo Guys wearing The Suits for Making Things Happen this OffSeason! Let’s Continue to Build! Welcome #SuperMario!,” he wrote.

The Bills flew Williams into town by private jet from his home in North Carolina shortly after the free-agency period opened at 4 p.m. ET Tuesday. Williams had informed the Bills on Tuesday night that he planned to visit other teams, two sources told ESPN.com’s John Clayton.

After quarterback Peyton Manning, Mario Williams is regarded as one of the top free agents available. And that means the Bills would have to pay a hefty price if they intend to land the player selected first overall in the 2006 draft by Houston.

Mario�Williams

#90 LB
Houston�Texans

2011 STATS

• Tot11
• Solo10
• Ast1
• FF1
• Sack5.0
• Int0

The Bills have identified improving their pass rush as a top offseason priority after managing just 29 sacks — including 10 in one game — last season.

Listed at 6-foot-6 and 285 pounds, Mario Williams is a two-time Pro Bowl starter, who had a Texans’ franchise-best 53 career sacks, including a team single-season best 14 in 2007. Williams was limited to playing just five games last season as a result of a torn chest muscle. He also missed three games in 2010 after having surgery to repair a sports hernia.

The Bills are coming off a 6-10 season, and have missed the playoffs for 12 straight years — the NFL’s longest active drought.

Information from ESPN NFL Insider Adam Schefter, ESPN.com senior NFL writer John Clayton and The Associated Press was used in this report.