Brazilian Luiz is under contract until 2015 but Chelsea and Manchester City want to sign the defender and reports in Portugal have indicated his club could be ready to cash in.
The 23-year-old has a release clause of over £40million in his current deal but £25m may be enough to tempt Benfica into selling.
Up in the air: Luiz (right) cannot guarantee he'll be at Benfica in 2011
City were prepared to pay that amount in the summer while Real Madrid and Barcelona have also been monitoring Luiz's situation.
AC Milan fancy their chances of signing the player and hope to use another Brazilian Thiago Silva to talk his close friend into moving to the San Siro.
Luiz, who recently turned down a new contract with Benfica, will not be short of options if he does decide to leave.
He said: 'My future, only God knows. I do not know where I will be in January, in the summer or in 2015,' he said.
'The rumours from England? I know that and I follow them, but this does not depend on me.
'I refused another renewal because I have a contract until June 2015 and am happy here. I have a clear conscience.
'If it were only a matter of money, I would not be at Benfica. Criticism hurts me but my mission is to work every day.'
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