The Telegraph says his release clause is a staggering €15m - which is partly why the most talented young coach in European football is set to stay at Porto for at least one more season.
Chelsea have discussed hiring Villas-Boas, who was formerly on Jose Mourinho's staff at Stamford Bridge, to replace Ancelotti. Along with other leading European clubs, they are still closely monitoring developments at Porto.
It appears that the clause applies to this summer only. At the end of next season, it is understood the amount of compensation due to the Portuguese champions would be much lower, making it far easier for an approach to be made.