Sporting CP coach Ruben Amorim insists Viktor Gyokeres isn't for sale in January.
However, he accepts Sporting will be powerless should an interested club pay the Swede's 100m buyout clause.
Chelsea will have scouts in the stands tonight to watch Gyokeres against Porto.
Aware of the transfer rumours, Amorim fired a warning at Chelsea and anyother suitor.
He stated before the game: "He will only leave if someone pays the buyout clause in January."