Carvalhal left Sheffield Wednesday on Christmas Eve, and now will take charge of his first ever Premier League game.
The Portuguese manager’s side sits at the bottom of the table, five points adrift of West Ham United in 17th place.
Watford have enjoyed a stellar season under manager Marco Silva, despite a dip in form over the festive period they sit 10th in the league.
Watford could welcome the return of Miguel Britos and Isaac Success to their squad after injuries but captain Troy Deeney remains out through suspension and Will Hughes misses out through injury.
Silva mentioned on Roberto Pereyra, saying: “Yesterday he started again to work with the team. The injury is nothing special. We'll take care with him and see how he is but he looks in a good condition to play tomorrow.”
Wilfried Bony may return from a hamstring injury that has kept him out of the past two games, but Ki Sung-Yueng and Kyle Bartley will miss the game.
Carvalhal has been a long-time admirer of the 4-3-3 shape – and even wrote a book on the formation – but often used 4-4-2 at Sheffield Wednesday.
Silva isn’t worried about the famous new manager bounce that could hit Swansea after Carvalhal’s appointment, claiming: “We've already analysed our opponent tomorrow,
“It's a new coach but it's not the first time. I remember the game against West Ham and it was the first game of [David] Moyes.” The 40-year-old said. “We did well - it's not the first time and we will keep focused on what we need to do to win the match.”
While the new Swansea manager said: “I never played any game in my career to draw,
“Even when I was coach of a third division team in Portugal and we played teams from the first division, we played to win.” After claims he might be happy with a point away to the Hornets. “That’s why we got into Europe.
In September Watford claimed a 2-1 victory at the Liberty Stadium after Richarlison scored the winner in stoppage time.
Andre Gray gave the Hornets a lead early on, and Tammy Abraham equalised in the 56th minute before an error by Roque Mesa and Alfie Mawson allowed the Brazilian forward to nick all three points.
Swansea have only won one of their last six games against Watford, with five of those coming in the Premier League.
Watford: Gomes; Janmaat, Britos, Wague, Kabasele, Zeegelaar; Cleverley, Doucoure; Carrillo, Okaka, Richarlison.
Swansea: Fabianski; Naughton, Fernandez, Mawson, Olsson; Sanches, Mesa, Carroll; Narsingh, Abraham, Ayew.