Divock Origi was not included in Liverpool's travelling squad for their Champions League opener against Napoli after twisting his ankle in the 3-1 victory over Newcastle at the weekend.
Origi was withdrawn before half-time against the Magpies as Liverpool continued their 100 per cent winning start to the Premier League season.
Reds manager Jurgen Klopp said on Saturday Origi would undergo a scan and was hopeful the issue was "not that serious", but the Belgian striker was absent from the 20-man group that will travel to Naples on Monday afternoon.
Teenager Rhian Brewster has taken Origi's place in the squad as Liverpool begin the defence of their European crown against a side that have finished Serie A runners-up in three of the last four seasons.
Fellow forward Sadio Mane and full-back Andy Robertson have been cleared, as expected, after Klopp confirmed the pair suffered minor knocks at the weekend.
Midfielder Naby Keita and goalkeeper Alisson Becker remain sidelined but Klopp said last week he is hopeful the former will start training soon, having not featured since the Community Shield because of a hip/groin concern.