Federico Chiesa was Liverpool's sole addition to their first team squad during the summer transfer window, but fans have seen little of the Italian forward to date.
The 26-year-old Italian international joined the Reds from Juventus for a bargain price of £10million, rising to a potential £12.5m.
Liverpool believed they had signed a player to add further depth to a forward line that includes Mohamed Salah, Luis Diaz, Darwin Nunez, Diogo Jota and Cody Gakpo.
Chiesa has only played 78 minutes for Liverpool to date, with his only start coming in Liverpool's Carabao Cup victory over West Ham last month.
Liverpool head coach Arne Slot confirmed Chiesa had been left out of his squad for their Champions League match with RB Leipzig on Wednesday.
Federico Chiesa was left out of Liverpool's squad for their Champions League tie at RB Leipzig
Liverpool boss Arne Slot has explained the winger's ongoing absence from his squad
Chiesa played just 78 minutes for Liverpool since completing his £12.5million summer move
Chiesa had also been left out the squad for the Reds last two Premier League fixtures and their Champions League match with Bologna last month.
Slot insisted Chiesa's absence is due to the Italian having missed pre-season and continuing work to get up to intensity of the rest of the Liverpool squad.
'With Federico it's a bit more simple; although it's more difficult, but it's a bit more simple to explain,' Slot said.
'He missed a complete pre-season, I said this many times, and going to a league where the intensity might even be higher than the Italian league. We just faced the two Italian teams so I can say this now.
'So that makes it difficult for him to make the step towards the intensity levels the rest of the team is at at the moment.
'That has not so much to do with the Italian league or the Premier League, that has more to do with him missing a complete pre-season and that is so difficult for every player – when the games are constantly there – to build them up towards the levels we are at.
'So, difficult to say, but it's a big disappointment for him that he is going in and out of the training sessions all the time. I feel sorry for him.
Slot suggested Chiesa is still working to get up to the same intensity levels at his team-mates
'But he signed a long-term contract so we will see what he brings for us. But at the moment, unfortunately for him he has been one or two times in the team selection and not more than that.'
Chiesa had been viewed as one of the poster boys of Italian football when he joined Juventus from Fiorentina.
The winger had starred when Italy were crowned European champions in 2021.
Chiesa's progress stalled when he suffer a cruciate ligament injury in 2022.