Lampard has resisted signing a long-term contract extension and, following the shock departure of coach Jose Mourinho, rumours persist the Barclays Premier League club are ready to cash in on the England international while they can.

Lampard has less than two years of his existing deal left and his value to Chelsea will diminish at a consistent rate while he fails to satisfy the club's desire to secure his services on a long-term basis.

Reports in Spain insist Lampard is already available for around £18million, with Juventus, Real Madrid and AC Milan all in touch with the player's agent Steve Kutner.

Chelsea know they cannot afford to let the situation drift on for much longer without a resolution one way or the other but Cole, on England duty with Lampard, made it clear that they could not afford to allow him to move on.

Cole said: "Frank is invaluable, one of the best midfielders in the world and the benchmark for getting goals from a midfield position.

"England missed Frank and Chelsea missed Frank and it is great to have him back in the squad - he is another world-class player here.

"There are a lot of players in great form in England at the moment and that is good news because all the best teams have competition for places."

Lampard missed England's last two qualifiers with a thigh injury and may sit out the Wembley clash with Estonia on Saturday because of the form of Gareth Barry.

Chelsea will risk the wrath of the fans for a second time if Lampard was allowed to leave but his close relationship with Mourinho may force their hand.

The club has managed to dispense with the colourful Portuguese and install new manager Avram Grant without too much dissent among the supporters.

Now, with former Ajax coach Henk ten Cate expected to be unveiled as a coaching assistant in the next 24 hours, much of the spotlight will fall back on the Lampard impasse.

Grant has so far fended off the question of the England player's future by citing the fact he has only been in charge for a matter of weeks.

But the crunch time will come with the January transfer window and, if the situation is not resolved by then, the England player may follow mentor Mourinho out of the door.

Meanwhile, another player close to his ex-manager has admitted the last month has been a testing time for him.

Portugal full-back Paulo Ferreira won the Champions League with Mourinho at Porto before following him to Stamford Bridge.

But Ferreira denies he has mourned the departure of Mourinho more than any other member of the Chelsea squad.

Ferreira said: "Nobody expected it. It was difficult for us, for me especially because I was working with him six years.

"He brought me to Porto and I came with him from there, so it's a lot of years with the same manager. It was difficult, but what can I say? Life goes on and you have to keep working and do your best."

Ferreira has gradually played his way back into contention for a place in the first team under Grant and that has boosted his confidence enormously.

His last two starts were against Manchester United and Valencia as Grant preferred his more defensive capability to the attacking prowess of Juliano Belletti.

Ferreira added: "It is good for me as well because I wasn't playing too much and now it's given me confidence. I need to play and I'm happy for that. I hope to keep playing like this."