Lampard has two years left on his current Chelsea deal

Lampard's contract expires in two years and he is in talks with Chelsea.

His agent Steve Kutner says he is aware of a clause in Fifa's transfer rules that means he could buy out the rest of his deal this summer.

Lampard is not set to use the clause but Kutner told the Independent: "He is as indispensable to Chelsea as anyone."

Under article 17 of Fifa's transfer regulations, players can unilaterally cancel their contracts after a "protected period" expires, if they pay "buy-out" compensation to their clubs, based on wages.

The three-year protection period on Lampard's current five-year deal runs out this summer, so he could theoretically leave then in exchange for two years' wages, believed to be around �8m.

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Kutner added: "We know about the rule and I've talked to Peter Kenyon, Chelsea's chief executive, about what Frank's worth to Chelsea, and what he's worth to other clubs."

He insisted Lampard's was indispensable, "not just creating goals and scoring them but as a marketing icon. His shirt sales outstrip any other player by four to one".

Earlier this year Kutner rejected a suggestion from Kenyon that Chelsea were "well down the line" towards agreeing a new deal with Lampard - although he insists he wants to stay at Stamford Bridge.

He said: "He has two years left on his deal and it's down to Peter Kenyon to talk to me, which I'm happy to do.

"If he wants to leave he could but that is nowhere near his mind at the moment."

Speaking to BBC Five Live, Kenyon said: "I think it is fair to say with John Terry and Frank we are well down the line with new contracts that will keep them at the club for substantially longer and I think that would be a big boost for everyone.

"We are involved in the best set-up, involved in one of the best English clubs why would they want to play football anywhere else?"

Lampard joined Chelsea in the summer of 2001 from West Ham and played a key role in the Blues' title triumphs in 2005 and 2006.