Bale trained with the club on Tuesday morning, along with Rafael van der Vaart, who is expected to feature against Milan despite missing three weeks due to a calf injury sustained in the 1-0 win in the first leg in Italy.
While Bale did appear in the 3-3 draw with Wolves on Sunday, it was his first appearance in six weeks following a back injury and Redknapp is unsure whether the Wales international will be fit to play a starting role against Milan.
"His back's fine but he was stiff in the legs," Redknapp said. "It's touch and go. We'd love to start with him but if he's not quite right I wouldn't want to take a chance. Van der Vaart has a good chance for Wednesday, I hope he'll be fit."
Redknapp was impressed by Bale's brief cameo display against Wolves at the weekend though.
"When Gareth came on and started to run with the ball, it was exciting," Redknapp said. "We've missed that for the last five or six weeks.
"That was his first real exertion for six weeks. He started straight away to run with the ball and when he does that, he scares people to death. He carries the game at the opposition and that makes a massive difference."
Bale, who was superb in both fixtures against Inter in the group stage, missed the first leg of the Champions League last-16 tie as a Peter Crouch goal put Spurs in control.
Corluka suffered an ankle injury following a nasty tackle from Flamini in the first leg on February 15. The Croatian was expected to be sidelined for a month, but he has trained freely in recent days and is in the frame to start at White Hart Lane.
"He trained and has worked hard in training the last week or two," Redknapp said. "He trained yesterday and trained today, so he is available. I have just a decision to make between him and Alan Hutton. We will look at that one tomorrow."
Flamini has done little to endear himself to the Tottenham faithful, being a former Arsenal man and feeling too much fuss has been made about his tackle on Corluka. And Redknapp excepts the crowd to single him out for criticism.
Redknapp said: "Flamini, he will get a hot reception regardless of what I say. The crowd are obviously going to give him a warm welcome I'm sure, but he expects that being an ex-Arsenal player coming here and a bad tackle in the first leg. He knows what to expect and I'm sure he's had it before."