Allardyce, who saw his side beat Norwich 2-1 on New Year's Day, claims he's unsure whether the two parties will be able to reach an agreement.
"Nicolas is an outstanding centre-forward," he said. "He's a great goalscorer. It would be great to have him here but there's always that one thing that holds it back and that's money. It would be lovely to have him but whether it's affordable for us another matter.
"Finance dominates and we can only spend what we can afford and what the chairmen can find."