After their stalemate with Porto yesterday, Benitez commented on the Muto deal.
Benitez said: “Muto is done but it's just waiting for the work permit. He played in the World Cup in a good team.
“He has done well in the Bundesliga so we are talking about a striker that is doing well in the last few years at international level.
“He has quality and can bring us energy and good movement plus the intensity you need. I don't see any problem with him."
But Benitez is now looking for another centre-back after getting bad news about Florian Lejeune from yesterday's game.
He said: “It is a cruciate ligament and he will need an operation.
“We need to decide exactly when but we will lose him for a while. It's bad news for us."