A decision has to be made by the FA, for whom Trevor starts work next year as director of football development, by Saturday.
If the appeal fails, Jermain faces another five match ban, meaning at the end of it he will have missed 12 games through suspension this season already - over a quarter of the campaign.
But Trevor insists that Jermain was unfairly punished and says:
"We will have to wait and see what the decision is on the appeal but I must say I think it will be extremely unlucky if it is not turned round.
"The discussion is all about intent and he would be a big loss."
He also says, however, that if the club, and Jermain himself, have to bite the bullet there are still plenty of options up front to replace the man who has scored 15 goals already - despite missing seven matches through suspension thus far.
"Jermain produced a good finish against Forest, and he is always going to be a livewire who scores goals," he says.
"But there is Brian Deane to come back to fitness, Marlon did well when he went through the middle, David has been a bit unlucky but he is working hard for the team and Neil Mellor is fit again, so we have still got some good quality strikers.
"It will be a big bonus though if Jermain was there amongst them in January and to say that was his last game for the club against Forest is far too premature."
Trevor is unfazed by the constant talk about Jermain and adds:
"Until January 31st, the speculation will continue, but he was delighted with his goal and he is happy scoring goals, so let's hope it is still with West Ham.
"There is speculation and each day you pick up the paper Jermain is going somewhere, Jamo is going somewhere, Michael might be going somewhere, and that is not going to go away until the end of January."