The former Barceloa and Chelsea winger, now 37, is a key player for coach Marco Baroni this season.
Lotito told Il Messaggero: "We decided not to sell him and he was included in the UEFA list because he is an exemplary champion. He always trains with hunger, he sets an example.
"I do not rule out a renewal, if he continues at this rate. He is an intelligent person and the results are visible."
Lotito also insisted they would be signing permanently on-loan Arsenal fullback Nuno Tavares.
He added, "Already a capital gain? I wouldn't sell him even for 70 million. We have beaten off a lot of competition from the big clubs for the full-back. I no longer want names but fighters. And it's not just Nuno, the others too. The purchases we have made are strong."