The Leicester City striker is said to be surplus to requirements at Walkers Stadium and is looking for a new club, as well as that he would be a free transfer.
But Warnock said: "I don't think we would be able to afford Brian to be honest. I'd love to have him, but I don't think anything will come of it."
However Warnock is confident of concluding various deals in the near future. "I'm optimistic things will get sorted next week," he added.