West Ham could be without Manuel Lanzini for up to a month following a stall in his recovery from a knee injury.
Lanzini has only seen 45 minutes of action, training alone throughout September and struggling to make adequate progress with his recovery.
"Lanzini is as close now as he was a couple of days before he started to train before the Newcastle game (in August)," said Bilic.
"He's doing everything but he is not training with us as in one movement he still feels the injury. We don't want to risk it.
"He's going to be definitely be ready after the international break. Will he be ready before, for the Swansea game? Hopefully… is it 100 per cent? No. You have the things that you hoping for — a timetable — and then you have a much more realistic timetable."