Bale, who joined Real Madrid from Tottenham Hotspur for a record 100 million euros (£85.3 million) on Sunday, has not played since July and Wales will not be taking any risks with him in Macedonia on Friday or at home to Serbia next Tuesday.
"He is not carrying an injury as such, he is not fit in terms of we could consider him for 90 minutes," Coleman said on Sky Sports News.
"He's going to train with us this afternoon. He's obviously had a lot going on physically and mentally but he's with us, that's the main thing.
"Is he going to start on Friday? I think that's a big question, a big doubt."
Wales are fourth in Group A and have admitted they have no chance of qualifying for next year's World Cup in Brazil. Belgium lead the group on 19 points with Croatia on 16, Serbia on seven and Wales on six.
Coleman is all too aware that Real Madrid would not be pleased if Bale were to pick up an injury on international duty.
"They are not our players, we borrow them, and we have to hand them back in at least the same state as what they arrived otherwise the relationship you try to build with clubs comes crashing down and that's no good," he said.
"If there's any chance he's in the red zone in terms of he could get injured, then he is not going to participate."
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