The 24-year-old, who signed for Madrid for a reported world-record £85m, has suffered from injuries and a lack of match fitness, but came on from the bench during the 2-1 win over Juventus in the Champions League in midweek.
"I'll see what happens in training and then I will make the decision to put him in or not," BBC Sport quotes Ancelotti as saying.
"It's true that he didn't have an easy time and he's worked hard. He used the [international] break to improve his condition, and, in my opinion and his opinion, he is ready to play from the start. He's ready. We're going to see the best of Bale now."
Madrid are currently third in the league table, three points adrift of leaders Barcelona.