The former Tottenham striker says he'll be ready should he be called upon.
He said, "My second match with Napoli and immediately I find the Champions League finalist who beat us in the final. I can't wait to play and help the team, if I have the opportunity.
"We have the dream of giving 100%, Liverpool started the championship in incredible form, the most important thing when we meet teams like this is that we don't make mistakes, Liverpool have players with so much quality, it's very strong on the break, they don't make mistakes. We have to be very careful and play a great game, giving the maximum, each one of us."