The 24-year-old made 17 appearances for Barcelona in the first half of the 2017-18 campaign before joining Watford on loan during the January transfer window.
The Spaniard has scored once and provided one assist in five Premier League appearances for the Hornets, although he has missed seven of the team's last eight league matches with a fractured foot.
Deulofeu has suggested that he doubts he will return to Barcelona this summer, and has talked up a permanent move to Vicarage Road.
"It's clear that I will not be returning to Barca," Deulofeu told Cadena Ser. "I do not think the coach would want me back at Barca and I have been told by Watford that I am wanted, so it could be that I stay at the club.
"I cannot say what will happen and we must wait but now I'm back from my injury and now I hope to finish the season strongly. I need to remain calm and make the right decision but a Barca return is not likely."
Deulofeu made his return from injury as a late substitute in Watford's 2-0 defeat at Tottenham Hotspur in the Premier League on Monday night.