According to The Liverpool Echo, Jota could not join his teammates in training after he asked to be substituted in Portugal's defeat to Spain this week.
The injury problem will be hugely frustrating for manager Jurgen Klopp as Jota has only played three times so far this term. The attacker suffered a hamstring injury in preseason and hasn't been able to start a Premier League encounter during the campaign.
Jota has been a key part of Klopp's attack ever since he moved to Anfield from Wolverhampton Wanderers in 2020, scoring 34 goals in 88 appearances across all competitions. His form even dispalced Roberto Firmino as Liverpool's first-choice center forward, but his 55 games last season appear to have taken their toll.
The setback will be hugely disappointing for the German boss, especially considering their stuttering start to the season. The Merseyside club have won just two of their six Premier League games so far and lie eighth in the table.
Klopp could be short of attackers in the Anfield clash with Brighton, with Luis Diaz only returning from international duty on Thursday morning. Darwin Nunez is also recovering from a knock.
Jurgen Klopp reveals why attacking duo missed Liverpool training session
The Reds will be desperate for a win on Saturday to kickstart their stuttering season. They face a Brighton side that will play their first game under new coach Roberto De Zerbi.
Liverpool have numerous problems to contend with after the international break, with Andy Robertson being a notable absentee for the weekend clash. Klopp was asked to explain why Jota and Nunez missed Friday's training session, to which he replied (as per The Liverpool Echo):
"Some are still out, that's Andy Robertson, that's Curtis Jones, that's Alex Oxlade-Chamberlain, that's Naby Keita. Definitely these four [are out].
"Diaz and Jota? Yes, they came back from the international duty and it's how it always is [after] a long flight. I didn't see them yet, I have heard they are good. Darwin was a precaution after the games. Same for Diogo. That's it, I think."
The German boss also commented on young right-back Calvin Ramsay, who is yet to play for the club following his summer move from Aberdeen:
"Calvin is not ready to play, but I am over the moon that he can train now. That's really good.
"He just needs to train, train, train. And he will probably play for the Under-21s and he can get a game there, because we play now all the time, that's fine."