The winger has been out of action since the end of January after struggling with a calf problem.
Pereyra has been in fine form for Watford this season and he is the club’s joint top scorer, alongside Troy Deeney, after netting six times this season.
And the Argentina international is fit to make his comeback on Friday when Watford travels to Cardiff, with right-back Kiko Femenia the only player unavailable due to a hamstring injury.
Cardiff could move four points clear of the Premier League relegation zone if they beat Watford on Friday.
Neil Warnock’s side has won their last two matches in a row to boost their survival hopes, and they return to action following a 13-day break.
In that time Warnock and Cardiff chief executive Ken Choo have been to Argentina to attend Emiliano Sala’s funeral.
Cardiff would move up to 13th place by claiming a third successive top-flight win, something they have not managed since April 1961.
Team News of Cardiff City vs Watford
Cardiff are hoping midfielder Victor Camarasa will be fit to start against Watford following a calf injury.
Camarasa, who came off the bench against Southampton, could be joined in the squad by Sean Morrison, five weeks after he had an appendix operation.
Watford trio Roberto Pereyra, Isaac Success, and Sebastian Prodl are available after injuries.
Kiko Femenia, who has a hamstring problem, is the only player unavailable to head coach Javi Gracia.
Cardiff hope Victor Camarasa will be fit enough to start. He has been troubled by a calf injury since the start of January but he made a cameo appearance from the bench in Cardiff’s last game, a 2-1 win at Southampton.
Defender Sean Morrison has stepped up his recovery this week after an operation to have his appendix removed, and could rejoin the squad.
Watford will welcome back Roberto Pereyra and Isaac Success.
Pereyra (calf) and Success (hamstring) have both missed the last three matches but will travel to South Wales.
Defender Sebastian Prodl is in contention to make his first league appearance since October. Kiko Femenia (hamstring) definitely misses out.
Score prediction: Watford 1-1 Cardiff City
TV channel and live stream, and online coverage
The match will be shown live on Sky Sports’ Premier League and Main Event channels and is available via Now TV with a day pass on offer for £7.99.
Sky Sports subscribers can stream the match online via SkyGo and the SkyGo app.
You can follow all the action with NewGersy Sport’s LIVE blog.
The two sides have faced each other 21 times in the Premier League, with West Ham boasting 12 wins to Fulham’s four. There have been five draws.
In their last meeting at Craven Cottage in mid-December, goals from Robert Snodgrass and Michail Antonio secured a 2-0 victory for the Hammers.