The Reds were close to an unprecedented quadruple of major trophies last year. In the four months since the loss in the final of the European club competition, the coach is wondering if his team needs to "reinvent ourselves".
In their first seven games of the season, the Reds have two wins and two losses.
Jonathan Woodgate said that the Reds lacked energy.
Rio Ferdinand and Michael Owen both said that the defeat could be a season to forget.
After a shaky start to the season, is it time to make changes for the sake of the team?
At the half-time break, they were down by three and it was their worst loss in the competition.
"We played bad in the first half but usually we don't concede three goals," said the coach, who has seen his squad hit by injuries this season.
You have to be very bad for that to happen with Alisson in goal. We have to change ourselves. A lot of things are missing.
They can't stop laughing because we have Wolves on Saturday. It is the right time to play them. In a lot of things, we have to set up better.
There are always options in football. It's obvious that we don't play well enough and that's the reason we lose games. I need time to think about what I have to do.
The players need to get back to basics according to Andy Robertson.
We were too far away. He said that you cannot come to a place like this and not be small.
This result was deserved by us. You have to be prepared. We were too far away from our mates. We have to wake up quickly because we cannot do that.
In Naples, Trent Alexander-Arnold and Joe Gomez struggled against the Italians.
The first goal came from the spot in the fifth minute, before the other two made it 2-0 at the half.
Two minutes into the second half, Zielinski scored his second goal, and by the time LuisDiaz scored, the damage had already been done.
Jamie Carragher described it as a "defensive shambles", while ex-Reds defender Rio Ferdinand said you could see the anger with the manager.
"That's a big statement to make, and the cutting comment is'we have to reinvented ourselves'," said Ferdinand.
The players are going to be grilled. It's not possible to have players where you question their desire. With the way the team is playing, he isn't getting the commitment he needs to succeed.
There are not many times where a team lacks desire and fight. Too many of their big stars aren't close to what we're used to.
Owen said thatNapoli had strength and desire, but it was a catalogue of errors from the other side of the pond. Fans of the club have been anticipating it for a long time. In the last few weeks, they haven't been good.
It's too good a manager to not find a solution.
He said he needed time to think about it, as he has won every domestic trophy with the club.
We weren't compact defensively or offensive.
I don't know why it happened but everything is obvious. It is difficult to take, but I have to do it.
In the news conference on the day Thomas Tuchel was fired, he was asked if he was worried about his own position.
Our owners are calm and expect me to sort the situation and not think someone else will, he said.
The contrast in performances between last season's efforts and those of 2022-23 has been stark.
Their next match is against Wolves on Saturday, and they don't have much time to think about it.