The Bafana Bafana international arrived at White Hart Lane during the January transfer window from Premier Soccer League outfit SuperSport United, for a fee believed to be in the region of £1.5m.
Khumalo has not feature for Spurs other than in training-ground friendlies, but was on the bench for the club's Premier League victory at Blackburn Rovers in midweek.
Redknapp, who has a defensive crisis on his hands at present, admits that the 24-year-old cannot be thrown straight into the action as the level of football in England is much higher than that of South Africa.
"He is fit to play. I think the Premier League is better than the South African league," the Spurs manager said.
"I know it's been compared to it but I just think it is a better league than the South African. There is a difference.
"He has to get used to the Premier League so let's hope he does. It isn't a case of adapting, it's a case of whether you're good enough.
"He is a fantastic boy who we think has a good chance of being a really good player so we have taken him, and he has come from South Africa and we love him to bits.
"He wants to be a player but he is a young kid really who has got lots to learn - but he wants to learn and he has the raw talent.
"We were going to loan him out to a Championship team, and that would have been good for him, but he is now in my squad because of players being injured."
While Khumalo may not be featuring for Spurs just yet, he has been included in Pitso Mosimane's Bafana Bafana squad to face Kenya on Wednesday.