Prem pundit Robbie Savage says Liverpool are coming to an end of their "cycle".
Writing for the Mirror, Savage said: “I said three weeks ago that Jurgen Klopp and Liverpool needed a rebuild, a reinvention.
“I got hammered for that, but it is true. Perhaps Jurgen reads the column!
“I have watched their games, and see their midfield. I am a huge fan of Jurgen Klopp, but every team has a cycle. I wonder about the body language and desire.
“Klopp's teams are supposed to play heavy metal football with intensity from back to front, and aggression. Against Napoli they were not right defensively. Even Virgil van Dijk. The positioning, the body language. The recovery runs are lethargic.
“I ask: have Liverpool been worked out? That performance at Napoli was the worst half of football under Klopp. The standards they have set are there to see. So is what they have achieved. They are one of the greatest Premier League teams.
“Something needs to be done quickly. Klopp is an unbelievable manager and I hugely admire him. But now he needs to call on all his managerial skill. It's a fascinating test."