The £20m summer signing from Roma came into the club as a replacement for Xabi Alonso but he has spent most of his time at the club warming the bench or not in the squad at all because of his ankle injury.
Despite claiming to be fit, the Italian international has still hardly featured despite the injury problems at the club.
But Benitez denies any problems and says he is just being cautious with his hamstring injury.
"He has been out for longer than we expected and, because he has been injured during the summer, he couldn't train properly," the Spaniard told the Telegraph.
"When you have a player who is not fit, he is always going to need time to settle in to a game. If the game is tight and he makes mistakes, then you have a problem.
"We want to protect the player but, at the same time, we want to keep winning games. He understands that he needs to be a little bit fitter before he can play."