Head coach Walter Mazzarri admits he still does not know the length of time Roberto Pereyra will be out injured.

The former Juventus midfielder suffered an injury to his meniscus during Watford's defeat at Manchester City on Wednesday which could reportedly sideline him for four months.

But Mazzarri could not specify the amount of time the summer signing will miss due to his knee injury.

The Hornets boss said: “About the length of time out I don’t know. I know that he injured his meniscus and we are not sure how many months it will be but we will see in the next days his rehab programme."

Watford also picked up another injury during today's 1-0 defeat at Sunderland with Sebastian Prodl forced off in the first half.

But Mazzarri does not think it is serious with the defender hopeful of being fit for the Crystal Palace home game on Boxing Day.

The Italian said: “I didn’t have time to check on him yet but he had a knock on his quad which shouldn’t be anything too serious."