The club increased their terms before last night's Capital One Cup tie against Oxford as outside interest in the Senegalese forward continues to grow.
Diouf has been with the Whites on non-contract terms for more than two weeks now but their move to offer a fresh proposal could see an agreement in the next 24 hours.
"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."