Bale has been struggling with a back injury and missed the clash at Sunderland at the weekend.
“I’d like to be able to scare Milan and say he’s going to be available, but he’s not,” Redknapp told Sky Sports News.
“He’s struggling to get over this back injury.
“The specialists don’t see too much of a problem there. There’s nothing that should keep him out too long.
“They looked at Crouch’s back and he has an epidural and Gareth had similar problems. Crouch’s looked an awful lot worse.
“Gareth’s has taken a little bit longer to heal. We’ve got to make sure he’s right. He’s a young lad and he’s very important. He’s got a great future in front of him.
“He doesn’t feel he’s ready to play. We leave it to him. At Sunderland he worked with the fitness coaches on Sunday morning and when they started to push him a bit he couldn’t go on.
“We’ve got to take our time and make sure he’s right when he comes back.”
