Fabian Hurzeler said a minor injury ruled Tommy Watson out of his matchday squad.
He expects to see him back when action resumes following the international break.
The winger signed from Sunderland was not part of the matchday 20 as [Albion](https://www.theargus.co.uk/sport/albion/?ref=au) drew at Crystal Palace.
He had come off the bench in recent games.
As expected, Kaoru Mitoma also missed the game and now has two weeks to further recover from an ankle injury which will have ruled him out for almost two months by the time fixtures resume.
Mitoma had been withdrawn from two Japan matches in Tokyo over the coming fortnight.
Brajan Gruda was shown out on the pitches training in a photo published by the club on Saturday.
It showed him smiling for the camera but it was not clear exactly what work Gruda was doing.
Asked about Watson after the Palace game, head coach Hurzeler said: “Small issue. He will be back after the international break.”
Albion again started with Diego Gomez to the left and also had Ferdi Kadioglu raiding up that side.
They resume Premier League fixtures when Brentford visit the Amex a week on Saturday.