Bale was again a spectator in Hong Kong as Tottenham recorded a 6-0 Barclays Asia Cup thrashing of South China.
The Welshman has failed to recover from a buttock injury, although conspiracy theorists point to the timing of his absence, which has coincided with intense speculation about a bid from Real Madrid.
Villas-Boas refused to discuss Bale's future, but he insists the £80million-rated winger will be training again after Tottenham have returned to England.
"He is going to be fit to join the team for training on Wednesday," he said.
"There is a big possibility he could be fit for Monaco.
"He hasn't done any training with the team yet but in all of the pre-season friendlies we had before he was involved.
"We are confident he will be able to join us."