With the Darrelle Revis holdout dominating headlines for three weeks, the New York Jets quietly have been negotiating a long-term extension for All-Pro center Nick Mangold. The two sides are close to a new deal that likely will make Mangold the highest-paid center in the league, league sources told ESPN.com.

Mangold, reached Sunday night at his home in New Jersey, declined to comment, saying he wanted to speak with his agent Monday before discussing it publicly. But a source close to Mangold said, "It should be done any day now."

A Jets spokesman would not confirm the deal.

Mangold, a first-round pick in 2006, was entering the final year of his rookie contract. Because of an escalator, he was due to make $3.3 million. In the spring and leading into training camp, Mangold expressed his displeasure with his contract, saying the two sides had barely spoken to each other.

At one point, Mangold hinted he might not show up for training camp. Ultimately, he decided to report because he wanted to "be there for my teammates and the coaches, and we'll see how it all plays out."

General manager Mike Tannenbaum, in a stalemate with the Revis camp, turned his attention toward Mangold, one of the team's core veterans. Details of the contract weren't immediately available, but the benchmark is believed to be Jason Brown of the St. Louis Rams. In 2009, Brown signed a five-year, $37.5 million deal that included $20 million in guarantees, making him the highest-paid center.

Mangold's deal was complicated by the 30 percent rule in the CBA, but the two sides evidently found common ground and worked around the restrictions. The 30 percent rule states that, in an uncapped year, a player's salary in an extension can't increase by more than 30 percent of his previous year's salary.

This is a significant move for the Jets, who have locked up the two centerpieces on their vaunted offensive line. In July, left tackle D'Brickashaw Ferguson signed a six-year, $60 million extension. Ferguson, too, was a first-round pick in 2006, Tannenbaum's first year as the GM.

In the spring, the Jets' chances of re-signing their so-called "Core Four" appeared bleak. Now it's two down, two to go -- Revis and linebacker David Harris. Harris, an emerging defensive star entering the final year of his rookie contract, is seeking around $9 million per year.

The Mangold deal should intensify the pressure on Revis, who has rejected long- and short-term proposals. Revis, signed through 2012, is due to make $1 million this season, which would bring him to $16 million over his first four years. He's seeking about $16.5 million per year, which would surpass the Oakland Raiders' Nnamdi Asomugha as the highest-paid corner.

Revis has told friends he won't report until he receives a new deal. The negotiations turned contentious at the start of camp, with the two sides trading barbs through the media. Finally, they released a joint statement, claiming that negotiations would be kept confidential.

John Clayton is a senior writer for ESPN.com. Rich Cimini covers the Jets for ESPNNewYork.com.