Schalke defender Naldo has warned his teammates to be wary of Mario Balotelli in the Europa League match against Nice on Thursday, saying: "He is still a super player."
Balotelli joined the Ligue 1 side after an unhappy spell at Liverpool and scored twice on his debut in a 3-2 win over Marseille.
Naldo told Bild: "Balotelli had a difficult phase, but he was very good in both attack and defence against Marseille. We should not allow him any space."
Schalke's former Manchester City defender Matija Nastasic, an ex-teammate of Balotelli, said: "He's a dangerous attacker. He had a few problems with his coaches in the past, but is now fully focused on football and can do outstanding things."
Following a summer of change at the Veltins Arena, FC Schalke have yet to get their campaign off the ground.
The Royal Blues have already suffered two Bundesliga defeats and hope to turn their form around in the Europa League.
In an interview with Der Westen, keeper Ralf Fahrmann said he was looking forward to the game.
"It's going to be a very, very difficult but also attractive match," he said. "It's nearly a Champions League match."