Nicolas Pepe is expected to be fit for Arsenal's short trip to Hertfordshire on Sunday.
The forward did not feature for the Ivory Coast in the international break but head coach Unai Emery said he is ready to play at Vicarage Road.
Rob Holding (knee) is closing in on a return but the game could come too soon, while Hector Bellerin (knee), Kieran Tierney and Konstantinos Mavropanos (both groin) are further away as they step up their recovery.
Forward Reiss Nelson, 19, is another to have earned a shot in the starting XI this season and Alexandre Lacazette's ankle injury - revealed by the club after Emery's press conference - should present Nelson with more chances.
"It's our philosophy and our idea to give them chances to be with us in training and taking confidence and playing minutes and if they achieve the performance we want, then continuing," Emery said, when asked about his young players.
"They can take experience being with us, training with us, playing with us and also helping them with our experienced players and sharing with those players our way."
New Watford boss Quique Sanchez Flores will be without defender Craig Cathcart for the first game of his second spell in charge.
Cathcart sustained a tear in his thigh over the international break while playing for Northern Ireland and is expected to be out for two to three weeks.
The Hornets are also without club captain Troy Deeney after he underwent knee surgery in August.
Provisional squad
Watford: Foster, Gomes, Dawson, Kabasele, Janmaat, Holebas, Doucoure, Chalobah, Cleverley, Femenia, Hughes, Success, Pereyra, Gray, Deulofeu, Welbeck, Masina, Sarr
Arsenal: Leno, Martinez, Maitland-Niles, Mustafi, Luiz, Papastathopoulos, Chambers, Kolasinac, Xhaka, Guendouzi, Torreira, Willock, Ceballos, Pepe, Nelson, Ozil, Aubameyang, Martinelli.
