The Algerian was linked with a January switch to West Ham, while Marseille are also believed to be keeping close tabs on the player.
His impressive displays of late seem to have alerted Italian giants Napoli as well, with the Azzurri looking to sign a back-up for Gonzalo Higuain.
Slimani is adamant he is solely focused on the Lions, but admits he is flattered by the reported interest from Italy.
“Napoli? I am focused on Sporting. What worries me is the end of the season. I have to prepare and compete at the World Cup away from the rumours,” the Algerian said to Le Buteur.
“I am clearly flattered by the interest, but I am already at a big club.”
Slimani, 25, joined Sporting Lisbon from Belouzidad last summer and he showed a great deal of potential early on despite being mostly restricted to substitute appearances.
The Algeria international has since nailed down a regular starting berth and has managed 8 goals in just over 900 minutes of league football this term. He has also bagged five goals in seven World Cup qualifiers for Algeria.