Bale picked up a calf knock in training before Christmas and sat out the Copa del Rey second leg against Olimpic Xatvia, the Primera Division match with Valencia and the mid-season friendly against Paris St Germain in Doha on Thursday.
The world's most expensive player has been back in training with his team-mates this week, though, and Ancelotti has named him in his 20-man squad for the visit of Celta.
Whether the 24-year-old takes the field remains to be seen, however.
Ancelotti said at his pre-match press conference: "He will be in the squad, but I have to decide if he's going to play. He trained this week, he's well, he has no problems, but it could be we will wait a little more to have him in optimum condition."