FOXBORO – Vince Wilfork was not present for the New England Patriots' organized team activity on Thursday, which could be a sign that the nose tackle is unhappy with the lack of talks on a contract extension.

The OTAs are voluntary, though 76 of the 91 players on the Pats' roster were on the field for the third session this week, the first which media were allowed to observe.

But players have used this form of protest in recent years to help kick-start the discussion on a new pact or express displeasure with a current one. The Jets' Leon Washington skipped his team's OTAs last week, and Cardinals' receiver Anquan Boldin, who has been griping about his contract for months, hasn't been on the field for Arizona this offseason either.

One of very best at his position, Wilfork seemed frustrated in a February interview with the Boston Globe, saying he and agent Kennard McGuire hadn't heard from Patriots brass about an extension in a year.

Five weeks ago, however, the 27-year old told the Boston Herald that he was happy with the status of contract talks and envisioned himself spending the rest of his career in New England.

McGuire did not respond when asked to comment on Thursday.

Wilfork is entering the final season of his six-year rookie contract, which he signed in 2004. He is scheduled to earn $2.3 million for 2009, the result of reaching escalators in the deal.

Pittsburgh's Casey Hampton and the Jets' Kris Jenkins, other nose tackles in 3-4 defensive systems, are both slated to make just over $5.1 million each this coming season.

New England has several high-profile players entering the final year of their respective contracts in addition to Wilfork: Richard Seymour, Logan Mankins, Stephen Gostkowski and Kevin Faulk among them.

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Fourteen other players besides Wilfork did not participate in Thursday's session, including linebackers Tedy Bruschi and Jerod Mayo, safety Brandon Meriweather, defensive linemen Ty Warren and Jarvis Green, and running back Sammy Morris.

Bruschi's mother, Juanita, passed away recently, and that is most likely the reason for his absence. Warren underwent surgery to repair a torn groin after last season and may not be healthy enough to participate.

The rest of those not spotted: corner Mike Richardson, safety Ray Ventrone, offensive linemen Mark LeVoir and Al Johnson, receivers Brandon Tate, Tyree Barnes, and Shun White, and linebacker Tyron McKenzie.

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This and that from Thursday's session

-- Laurence Maroney fielded several kickoff returns during special teams work; he did handle kickoffs in games as a rookie but has not since. Terrence Wheatley and Darius Butler also had some kickoff returns.

-- Inside linebacker Paris Lenon, signed on Wednesday, was on the field and is wearing number 47.

-- Without Bruschi and Mayo, New England was very thin at inside backer, with Gary Guyton and Eric Alexander the lone returning players at the position.

smanza@projo.com