The 31-year old Senegalese striker has been with the Whites on non-contract terms for about two weeks but Warnock wants to tie him up for the season ahead at Elland Road.
"We've spoken to his man again and offered him an increased contract. Whether it's sufficient or not we'll find out," Warnock told the Yorkshire Evening Post.
"But that's why I brought him off. The crowd were fabulous when he left the pitch and I hoped that might just push him into signing.
"I've said to him, it's not about money. He's got enough of that. It's about playing in this stadium for a team like this. It's about realising what he can do for us."