Kaboul praises improving Bongani
South Africa international Khumalo arrived at White Hart Lane from SuperSport United in January, before quickly being sent out on a four-month loan to Championship side Preston North End.
The 24-year-old returned to London after suffering a foot injury in April and is currently with the Spurs squad as they tour South Africa, and Kaboul has been impressed by the improvement the Swaziland-born stopper has made.
"I think Bongani has been learning a lot since he got to England and I can see that because we play in the same position," Kaboul told Football365.co.za.
"He is very happy at the club. I think he has a big chance of making it in England and South Africans shouldn't panic when he is being sent on loan because the aim of that is to help him settle to European football by ensuring that he plays many games instead of him learning while warming the bench.
"The reality is, coming from Africa is very different to the football there and I know because I come from Morocco so you have a lot of things to learn like how they live, so I believe that step by step he can easily make it because he is definitely a quality player who deserves to play at the highest level.
Meanwhile, Spurs boss Harry Redknapp has played down reports that the defender could be loaned out to Scottish champions Rangers.
"Rangers did show interest, but I haven't spoken to Bongani about it," Redknapp said.
"I think it will do him good to go play somewhere on loan. It can only improve him. We are very pleased with him. He is a great lad with a great attitude."
Spurs are currently competing in the Vodacom Challenge, and will face South African side Orlando Pirates in their second pre-season match on Tuesday evening.