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The Oakland Raiders picked up DL Richard Seymour in a 2009 trade with the New England Patriots, and many analysts believe the Raiders came out ahead in the deal. (Dan Honda/Staff)

Richard Seymour doesn't believe in wasted emotion. Ask him about playing the New England Patriots, and he'll respond with a sly half-smile and an answer devoid of bulletin-board material.

"It isn't me against New England, it's the Raiders against New England," Seymour said.

His demeanor will undergo a dramatic change Sunday when the Raiders host the Patriots at a sold-out O.co Coliseum.

"Let me tell you about Richard," said former Patriots teammate and NBC analyst Rodney Harrison. "He's a quiet guy off the field, really laid-back. But when he gets on the field, he wants to rip your head off."

The trade just before the start of the 2009 season that sent Seymour to the Raiders for a 2011 first-round draft pick is a big topic in the New England area this week, and there is sentiment that this may be one of the rare times coach Bill Belichick came out on the wrong end of a deal.

"Since Richard left, there hasn't been that kind of presence on the defensive line," former teammate and ESPN analyst Tedy Bruschi said on ESPN radio. "He got that pocket pushed, and that's what they've missed."

In two full seasons without Seymour, the Patriots finished 11th in total defense in 2009 and 25th in 2010. They're currently ranked 32nd, giving up 468.7 yards per game.

New England traded for Albert Haynesworth and signed free agent Shaun Ellis this season as it continued to search for answers on the defensive line.

Asked on a conference call if the Patriots had ever adequately replaced Seymour, Belichick paused for a few moments before answering.

"I don't think, with top-level players, you ever get the same guy," Belichick said. "You construct other parts of your team. Even if you find a guy to play that position, they play it a bit differently."

With the pick the Patriots received for Seymour, New England took tackle Nate Solder with the No. 17 overall pick. Solder is starting at right tackle in place of the injured Sebastian Vollmer.

The Raiders consider Seymour, who turns 32 on Thursday, the leader of one of the strongest and deepest defensive lines in the NFL.

Seymour has repeated often that he loves it in Oakland and wouldn't want to play anywhere else. He made more than $12 million as an exclusive franchise free agent in 2009 and signed a two-year contract before the lockout that could pay him $30 million.

"They made a business decision," Seymour said of the Patriots. "I can't control what happens for them, but it's worked out well for me."

At the time of the trade, Seymour had no idea the Patriots deemed him expendable in part because they needed money for quarterback Tom Brady, nose tackle Vince Wilfork and guard Logan Mankins, among others.

Seymour said he'd been "blindsided" and took five days to get himself and his family used to the idea of playing for a new team.

"He was hurt because that was the team that drafted him," Harrison said. "But there's a point where this thing is a business, and he learned the business of football. A lot of times our experiences shape and form us.

"It made him a better person. It made him see things more clearly. He's in a place now where he has the respect he deserves. He feels like he's making an impact in the locker room, and he's the leader of that team."

Harrison, who believes Seymour to be at the top of his game, was incredulous when asked if the Patriots missed him.

"Are you crazy? I don't care if you bring Albert Haynesworth in," Harrison said. "Superman might be able to replace him, but you can't replace Richard Seymour."

Having been in so many big games in New England, Harrison takes Seymour at his word when he says he won't approach a game against the Patriots any differently from how he would the Jets or anyone else.

That means the Patriots will get what everyone gets -- a powerful, intense effort to the whistle and occasionally beyond as Seymour's aura of calm turns malevolent.

In 2006, Seymour drew a $7,500 fine for stepping on the head of Indianapolis tackle Tarik Glenn. With the Raiders in 2009, he was fined $7,500 for pulling the hair of Denver tackle Ryan Clady, and last season he was ejected and docked $25,000 for dropping Pittsburgh quarterback Ben Roethlisberger with an open hand through the face mask.

Former Raiders defensive coordinator John Marshall, a few days before the Roethlisberger incident, summed up Seymour this way:

"He's a professional who takes care of business. But as you watch film of Richard, he's not a very nice man on the football field."