Trent Alexander-Arnold has not travelled with Liverpool for their Champions League clash with Porto.
The right-back has not made the trip to Portugal on Monday evening and is a doubt for making this weekend’s Premier League tie against Manchester City, the Liverpool Echo reports.
Alexander-Arnold was seen in the Reds’ training session at their Kirkby base on Monday morning.
However, the club is still yet to confirm whether he has picked up an injury or not.
The England international faced Brentford last Saturday but did not play the two games prior to that, missing the game against Crystal Palace and being rested for the Carabao Cup tie against Norwich.
In the clash against the Eagles, veteran James Milner took his place with young Northern Irishman Conor Bradley stepping in for the cup tie.
But Wales international Neco Williams has returned to full fitness and has travelled with the squad to Portugal.
He has been out all season so far with an injury but could make his first appearance.
Joe Gomez is another option to fill in in Alexander-Arnold’s absence, although he may be needed in the centre of defence.
Aside from Alexander-Arnold, Thiago Alcantara and Harvey Elliot are still missing with longer term injuries.
At a press conference ahead of the clash on Monday before Alexander-Arnold’s absence, Klopp said: "A big squad will travel. 23 are with us and apart from the longer-term injuries, they are all in.
“No Thiago, Harvey and the rest available. No new concerns at the moment."
Naby Keita returned to training on Monday after missing the Brentford match and is fit for the game and travelled with the squad.
He had suffered from a minor foot injury but Klopp confirmed in a press conference that he would be making the trip to southern Europe.
Roberto Firmino made his return from injury with an appearance off the bench in the dramatic 3-3 draw against Brentford on Saturday.
The Brazilian striker has travelled with the squad to Portugal.
Liverpool got their Champions League campaign off to a winning start after a thrilling 3-2 victory over AC Milan at Anfield a fortnight ago.
Liverpool squad: Alisson, Adrian, Kelleher; Williams, Gomez, Van Dijk, Konate, Matip, Tsimikas, Robertson, Phillips; Keita, Milner, Henderson, Oxlade-Chamberlain, Jones, Fabinho; Jota, Origi, Firmino, Mane, Salah, Minamino
