The Atlanta Falcons informed Michael Vick and his representatives in a letter yesterday that they intend to force the quarterback to return a portion of the $37 million in bonuses that his 10-year, $130 million contract contains.

The Falcons' decision came as Vick formally entered a guilty plea in his dogfighting case in federal court in Richmond, Va.

The tussle for Vick's money is highly complex and could involve two separate arbitrators and a federal judge. Sources familiar with the issues said yesterday the NFL Players Association will contend that, based on provisions in the sport's labor deal and the precedent set in a recent case involving former University of Hawai'i star Ashley Lelie, the Falcons are entitled to try to retrieve no more than $6 million.

NFL Commissioner Roger Goodell suspended Vick indefinitely without pay on Friday.

At a news conference yesterday in Atlanta, Falcons President Rich McKay said: "With respect to pursuing his bonus money, we intend to do that."

McKay and Falcons owner Arthur Blank stopped short of saying the team would release Vick. Several people familiar with the case said they expect that to be the eventual result. But first, they said, the Falcons must keep him on the roster in an effort to force him to return a portion of his bonus money — a $7.5 million signing bonus and two roster bonuses totaling $29.5 million — paid out under the contract Vick signed with Atlanta in December 2004.

Now that Vick is suspended without pay, he will not receive his $6 million salary for the upcoming season, and the Falcons will be credited with that amount on their salary cap.

Vick was not in default of his contract during training camp because, while Goodell ordered him not to report to camp, the commissioner excused the absence. Vick's guilty plea and suspension now put him potentially in default of his contract.

Because he has eight seasons remaining on a 10-year contract, the Falcons could seek the return of 80 percent of his bonus money. That potentially could leave the Falcons attempting to retrieve up to $29.6 million, or 80 percent of $37 million.

The case involving Lelie (now with the San Francisco 49ers), and the extension of the league's collective bargaining agreement last year, might severely limit the amount the Falcons can recover. The labor deal says that "salary escalators already earned" are not subject to being retrieved by a team.

Stephen Burbank, a University of Pennsylvania law professor who is the NFL's official in charge of resolving disputes between management and the union arising from the collective bargaining agreement, ruled in the Lelie case that an option bonus (paid by a team to a player to activate additional option years at the end of a contract) fell under that category of "salary escalators already earned" that could not be retrieved by a team. The Denver Broncos had filed a grievance against Lelie last year.

The question in the Vick case, then, could be whether roster bonuses also fall into that category. If they do, the Falcons could be limited to seeking 80 percent of the $7.5 million signing bonus in Vick's contract — $6 million — as reimbursement.