Liverpool midfielder Georginio Wijnaldum is a serious doubt for the upcoming Club World Cup

Liverpool midfielder Georginio Wijnaldum is a serious doubt for the upcoming Club World Cup after picking up an injury.

The Dutch international was forced off the pitch in the second half of their 2-0 victory over Watford whilst holding his left hamstring in some pain.

Reds manager Jurgen Klopp has admitted he is still unsure on what the injury exactly is but revealed it could affect whether he travels to Qatar or not.

'It's a muscle problem,' said Klopp after his side extended their unbeaten season against the Hornets.

'I don't know. He could probably fly to Qatar, my problem is I don't know what injury it is.

'You never want a muscle injury for a player but at this moment it's more difficult. All teams have the same problems. Tomorrow we will know more.'

The German admitted he has had no issue with the jam-packed December schedule his side have been given but it has clearly come at a price.

He told BT Sport: 'Our main problem is about losing players. We are fine with the number of fixtures but losing players does not make it any easier.'

Wijnaldum will now join Fabinho, Dejan Lovren and Joel Matip on the sidelines as the injuries start to pile up for the Premier League leaders.

Klopp will likely re-shuffle his line-up on Tuesday night for their next match against Aston Villa in the EFL Cup quarter finals.