Cardiff hope Victor Camarasa will be fit enough to start. The on-loan Real Betis midfielder 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.
- Cardiff have lost just one of their last six home league meetings with Watford (W4 D1), though it was the last such match in December 2014 (2-4).
- Watford are looking to secure their first league double over Cardiff since the 2005-06 campaign, when they were in the Championship.
- Cardiff won their only previous Premier League game played on a Friday, beating Wolves 2-1 back in November.
- Cardiff are looking to win three consecutive top-flight league games for the first time since February 1961.
- Watford have kept a clean sheet in three of their last four Premier League matches, as many as they had in their last 21 in the competition. They're looking to record three consecutive league shutouts for the first time since September 2017.
- No team has scored more 90th-minute goals in the Premier League this season than Cardiff (5), with three of those being winning goals - also a joint league-high.
- 21% of Cardiff's Premier League goals this season have been scored by their substitutes (5/24), the highest ratio in the division.
- Cardiff have already won as many Premier League games this season (7/26) as they did in their previous campaign in the competition in 2013-14 (7/38).
- This will be Cardiff manager Neil Warnock's 38th meeting with Watford in all competitions (W13 D7 L17), making them the club he's faced the most in his managerial career. Against no other side has he lost more games than he has against the Hornets (17, also vs Reading).
- All 10 of Watford's Premier League victories this season have come with Abdoulaye Doucoure in the starting lineup, with the Hornets failing to win all four games the Frenchman has not started (D3 L1).
Referee: Simon Hooper
Assistants: Scott Ledger, Derek Eaton
Fourth official: David Coote