Liverpool midfielder James Milner was forced off early with a suspected hamstring injury during Sunday's match against Manchester City.
Milner pulled up moments after a challenge with City right-back Kyle Walker in the first half of the game at Anfield.
Sky Sports pundit Gary Neville says the injury may have been caused by Liverpool's busy schedule of recent weeks - Milner has played four games in the past fortnight.
Neville, speaking during the match, said: "We just had a conversation about the impact of three games in a week, really tough games, with the travelling, and that could be a sign [of fatigue].
"You can pull your hamstring in any fixture at any time, but you are more likely when you are fatigued. You're just not quite right."
Milner was replaced by Naby Keita, who underwent various medical checks after suffering a back spasm in Wednesday's defeat at Napoli in the Champions League.