Niculae, who spent five years at Sporting and played in the 2005 UEFA Cup Final defeat by CSKA Moscow, is aware of the interest.
But he insisted he is in no rush to leave Inverness and will be happy to see out the remaining year of his contract.
Niculae, who earns more than £4000 a week, said: "I know about things but do not want to be disrespectful to Inverness. I have a year left and it will not be a problem for me to stay next season.
"But if clubs make official contact with Inverness it is up to them what they decide to do. I will wait and see what happens.
"I'm just thinking about the Euro Championships for now as I'm enjoying it out here."