Wales boss Chris Coleman has confirmed that Bale has a groin problem and will only come off the bench in Cardiff.
"With him not playing any games he's not going to start on Tuesday and he never was,” Coleman told Sky Sports News.
"When you've had three to four training sessions in six to eight weeks, as good as he is, you can't be risking players."
He added of the decision to not use Bale in Skopje on Friday: "We can't alter the fact that the pitch wasn't great and he just feels something in his groin - a strain.
"He came to see me on Friday morning and said something didn't feel right.
"The scan is precautionary but he needs to know and be sure that there's nothing there. We don't think there is. If it's good news and he can play some part, of course he will. But ultimately the player says if he can or he can't."