Jordan Henderson will miss Liverpool's Boxing Day Premier League game with Swansea City due to a hamstring injury.
The midfielder required extensive treatment during Liverpool's thrilling 3-3 draw with Arsenal on Friday night and was taken off just shy of the 10-minute mark.
Henderson, 27, was replaced by James Milner who captained the side for the rest of the game.
Jurgen Klopp said: "The problem is that Hendo will not feature for sure, he is out."
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The Reds manager is concerned the England international could be ruled out for a large part of Liverpool's busy festive season schedule.
After hosting Swansea on Boxing Day, Liverpool are at home to Leicester four days later before travelling to Burnley on New Year's Day.