The Real Madrid forward has made just three appearances for the Spanish club since making his world-record move from Tottenham, and is currently sidelined by a thigh injury.
Wales boss Chris Coleman revealed Bale was not fit to take part, and that he had been included in the vain hope he may have been in a position to be involved.
"He is named until we're told otherwise," said Coleman.
"But after naming the squad I was told he had a problem. It looks like he will possibly be out for two weeks.
"I found out yesterday for definite. I spoke to the doctor and he filled me in on the particulars. You always hope because sometimes you have a slight problem but we like to try and get him here to see how serious it is.
"This is more than a slight problem. He will be unavailable for at least the first week of training, so he has no chance of playing.
"I don't want to waste his time, Real Madrid's time, or our time.
"It is a massive blow, we didn't have him for the Republic of Ireland game, we only had him for half-an-hour against Serbia.
"A player of his talent would be a loss to anybody, especially to us, offensively he is the key that opens every door."
Coleman's captain Ashley Williams is also a fitness doubt due the ankle ligament injury which has kept him out of Swansea's recent run of fixtures.
But he is included, despite Swans' manager Michael Laudrup's pleas for him to be given the rest required to fully recover from his injury.
There is, however, no place for West Ham defender James Collins.
Coleman was critical of Collins after last month's defeat to Serbia, claiming he had turned down the chance to join up with the squad with Williams suspended and Sam Ricketts injured.
Collins insisted he would never turn his country down and that he had not received a message asking him to join up, but Coleman has clearly decided the player was in the wrong and has omitted him.
There is a welcome return for Liverpool midfielder Joe Allen, who missed September's defeats to Macedonia and Serbia through injury, but Crystal Palace midfielder Jonathan Williams is absent.
Craig Bellamy is included for what looks likely to be his final competitive games for the Dragons.
The Cardiff forward has made it clear he does not see himself taking part in the Euro 2016 qualifying campaign.
The upcoming double header will be crucial for Coleman after the criticism he came in for after back-to-back defeats last month, the nadir of which came when he lost his passport and missed Wales' final preparations before their 2-1 defeat in Skopje.
Wales squad for World Cup qualifiers gainst Macedonia and Belgium: Hennessey (Wolves), Myhill (West Brom), Fon Williams (Tranmere), Davies (Swansea), Gabbidon (Crystal Palace), Gunter (Reading), Matthews (Celtic), Ricketts (Wolves), Taylor (Swansea) A Williams (Swansea, captain), Allen (Liverpool) Collison (Bournemouth) Crofts - (Brighton), John (Cardiff), King (Leicester), Ledley (Celtic), Ramsey (Arsenal), Vaughan (Sunderland), Bale (Real Madrid), Bellamy (Cardiff), Church (Charlton), Robson-Kanu (Reading), Vokes (Burnley).