Career Mode-players on international duty can’t sub

@iamchicharito14
For the record, this has been an issue since FIFA22, and EA has never fixed it.

Don't hold your breath, as I would be VERY surprised if they bothered now.

All you can do is back out of the match, go to the team management section and remove the player from the team sheet, replaced by another, save the change and then go back to the match start-up.