Watford head coach Walter Mazzarri fears Daryl Janmaat may have fractured his shoulder and the Dutchman could face a lengthy spell on the sidelines.

It was initially expected the injury, suffered in the win over Manchester United, would keep him out for up to six weeks but Mazzarri says the extent of the damage is not yet clear.

Mazzarri said: “We are evaluating his injury. We really didn’t need this now. It’s quite a bad injury but we will know the time how long he will be out in the next few days.

“It could be a fracture. It’s being checked and in the next few days we will know more. It might be a fracture.

“As you know we counted on him a lot and he was progressing and started playing in the squad the way I wanted him to play. But of course the person that comes in for him will be just as good.”

Defender Jose Holebas also has a slight abductor injury which could threaten his participation at Burnley on Monday night.

The Hornets boss said: “We have no more bad injuries but there are some players we need to evaluate. Jose Holebas we will know about today or tomorrow if he’s ok. A lot of the players after the Manchester United game need to be evaluated.

“Holebas has a bit of a problem with the abductor and I hope he will be ok. Before the Arsenal game he had a problem but then he was ok. We need to see today and tomorrow.”