Bale, who joined Spanish giants Real Madrid on a world record €100 million move from Tottenham last week, was an unused substitute when Wales lost 2-1 to Macedonia on Friday night.
Welsh manager Chris Coleman revealed the winger was left on the sidelines because of a groin injury suffered in training.
However, Bale's groin problem does not appear that serious as he trained with Wales after the scan, ahead of their World Cup qualifier against Serbia in Cardiff.
"We had a conversation with Gareth before the game, he had a tight groin from the day before and we could not take that chance," Coleman said on Monday.
"As we speak he has gone to have another scan on it to clear his mind so he knows everything is alright."
Bale has not played since mid-July due to a foot problem and his latest injury concern comes just days before he is scheduled to make his Madrid debut at Villarreal this weekend.
While Coleman revealed the 24-year-old suffered the problem during Wales' training session on Thursday, he is hopeful Bale can play some part against the Serbs.
"We went into the Macedonia game with everything great," Coleman said.
"Gareth gets his move to Real Madrid; everything is positive.
"Then Gareth picks up a strain in training and can't play in the game, which is disappointing.
"He was never going to be available to start either of these games but, at best, he would have come on for maybe half an hour.
"There is a small chance of that tomorrow (Tuesday) night. We will see when we get the scan results back and how he feels."
Bale is the only injury concern for Wales ahead of the battle with Serbia.
Crystal Palace midfielder Jonathan Williams has been ruled out after suffering an ankle injury, while centre-back Sam Ricketts is also in doubt.
Captain Ashley Williams is suspended after picking up a yellow card in Skopje, with either Aaron Ramsey or Craig Bellamy likely to take the captain's armband.
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