Defensive lineman Richard Seymour has agreed to a two-year extension with the Oakland Raiders that will make him the highest-paid defensive player in football, a team source told ESPN NFL Insider Adam Schefter.

Chicago Bears defensive end Julius Peppers makes an average of $14 million a year and while Seymour's exact numbers will not be known until he signs, the numbers will come in north of Peppers'.

SI.com first reported Seymour's extension. The website said Seymour's contract is potentially worth $30 million and contains $22.5 million guaranteed.

The 31-year-old defensive end went to the Pro Bowl last season, making a big impact in his second season in Oakland after being acquired in a trade from New England. He had 5½ sacks and provided leadership for a young defense that features two rookies starting in the front seven.

The Patriots own the Raiders' first-round pick (17th overall) in the 2011 draft as a result of the Seymour trade.

The deal allows Oakland to avoid using a franchise tag on Seymour for a second straight season. He got about $12.4 million last season and would have been in line for a salary of about $14.9 million next season with the tag. Instead he signed a deal that will keep him in Oakland for two more seasons.

"It's a great place to play," he said last December. "The fans are unlike any others in the league. They're definitely committed, and they want the same type players to play in this organization. The history of being here, the mystique of putting that silver and black on and representing the Raiders, it's been a lifelong dream for me and, hopefully, it continues."

The Raiders' deal to acquire Seymour was questioned by some because Oakland's picks recently have been so high in the draft. With the Raiders having their best season since 2002, the Patriots will pick 17th overall in April's draft.

"You may not think it was a good trade," Davis said last month. "I thought it was a great trade. Still do."

Seymour was selected to his sixth Pro Bowl last season, anchoring Oakland's defense after moving inside to defensive tackle. Seymour was praised by coaches and teammates for his play as well as his leadership on a youthful unit.

Seymour, 31, is a three-time Super Bowl winner with the Patriots and has 48.5 career sacks.

The Raiders have historically done a good job keeping potential free agents whom they didn't want to test the free agent market. They signed long-term deals in recent years with cornerback Nnamdi Asomugha, punter Shane Lechler and kicker Sebastian Janikowski instead of using franchise tags.

The final year of Asomugha's $45.3 million, three-year contract voided earlier this offseason when he did not reach certain incentives, making him one of the many key potential free agents for the Raiders.

The Raiders can't use the franchise tag on Asomugha, making tight end Zach Miller the most likely recipient if the team opts to use the tag.

Miller has led the Raiders in receiving for each of the past three seasons. He had 60 catches for 685 yards and five touchdowns last season.

Among Oakland's other key potential free agents are offensive lineman Robert Gallery, running back Michael Bush, safety Michael Huff, cornerback Stanford Routt and defensive lineman John Henderson.

Information from The Associated Press was used in this report.