Some people believed New England Patriots coach Bill Belichick had fleeced Oakland Raiders managing general partner Al Davis when Belichick traded soon-to-be 30-year-old defensive lineman Richard Seymour to the Raiders for a 2011 first-round draft pick.

Many of those same critics now are touting Seymour, acquired in September 2009, as a primary reason for the Raiders’ defensive success this season.

"Their front (four) is talented, deep and dictating the pace of games," said coach Mike Tomlin, whose Pittsburgh Steelers play the Raiders tomorrow. "I really think that the rest of their defense is riding an awesome wave created by the play of those men up front, led by Richard Seymour."

The Raiders boast the league’s sixth-ranked defense at an average of 309.6 yards allowed per game. That’s a dramatic improvement from the 361.9 figure last season, when the Raiders were 26th.

Many credit Seymour’s play, especially the past three games, with spearheading the turnaround. Suddenly, their decision to re-sign him in the offseason to a one-year, $12.4 million contract seems prescient.

Seymour was part of the 2009 defense that struggled most games. There were times his immense talent materialized as he played all four positions on the line — sometimes in the same game. But Raiders defensive line coach Mike Waufle said Seymour wasn’t being used correctly.

Waufle interviewed Seymour at the NFL scouting combine in 2001, about two months before the Patriots made Seymour the No. 6 selection in the draft.

Waufle, then in his first Raiders coaching stint, came away from the process convinced Seymour’s natural position is defensive tackle. So, Seymour was moved inside soon after rejoining the Raiders this offseason.

"For the first time in his career, he’s playing where he needed to play," said Waufle, who spent the past six seasons with the New York Giants. "And that’s being able to be in that A gap and that B gap, on and off the guard and on and off the center.

"He’s such a big, imposing figure that he can dominate a game from that position. He had to learn how to play it. It was new to him, a lot of the schemes. It took some time and development."

Fellow defensive tackle Tommy Kelly said Seymour now is able to rely upon his instincts and not get bogged down juggling the nuances of playing several positions.

"When you can just get in a spot and not worry about learning this and that — he doesn’t have to worry about (much)," Kelly said. "He doesn’t have anything on his plate. He can just concentrate on his man, and he doesn’t have too much of a problem with anybody."

Seymour’s rare combination of size, speed, strength and smarts compels teams to double-team him. In turn, players such as Kelly, the defensive ends and middle linebacker Rolando McClain are in better position to make plays.

Seymour, 31, said it took him a while to find his comfort zone after joining the Raiders. Not only was he switching teams, but he also was moving from the East Coast and learning a new scheme.

"I was feeling my way around, just taking the time to know my teammates, the coaching staff and the philosophy, and working my way to where I could be effective," Seymour said. "Obviously, with another year under my belt it has definitely paid dividends."

Raiders defensive coordinator John Marshall said Seymour is playing at an impressive level.

"I don’t like to compare players," Marshall said, "but he’s playing really high-level football. He’s been very productive. What’s really more important is, if he’s not making the play, he’s pushing the play to somebody else."

Steelers quarterback Ben Roethlisberger thinks Seymour, 6-foot-6 and 310 pounds, is playing as well as he has at any point in his career, which includes five Pro Bowl selections.

"The film that we’ve broken down, he’s playing the best football of his career," Roethlisberger said. "I don’t mean that as any disrespect to how he was playing before, but he would be my choice for MVP of, at least, that defense. He’s wreaking havoc on everybody and everything, and he seems to be rejuvenated."