Ntuli, who seemingly has no future at Sundowns, is currently away with the national team preparing for the second leg of the CHAN qualifier against Zambia, set to take place in Ndola on Saturday.
The 26-year-old striker has only played twice for Sundowns, both appearances coming off the bench.
He was loaned to Platinum Stars for two seasons and scored nine league goals in 38 appearances under ex-Dikwena coach Johnson.
When Ntuli joined Sundowns from Golden Arrows at the beginning of the 2014/15 season after Abafana Bes'thende were relegated, Sundowns loaned him to Usuthu for the second half of that season, where he scored six goals in 13 appearances.
"Bongs and I have been together for years on and off and I always have a good relationship with him," Johnson reveals.
"If needs be and [he's] available I think, again, we'll talk and see what personnel we have in order for him to fit into [the] Usuthu structure.
"I'm going to do it [approach Sundowns] but for now it is the team that I found here. Bongs is still with Bafana Bafana," adds Johnson, who likened his relationship with Ntuli to that of a father and son.
Meanwhile, former Kaizer Chiefs left-back Mtsweni is still training with Usuthu and it appears Johnson is quite impressed with what he has seen.
"I think he is a fantastic player and he's got a good left foot on him, he overlaps very well and he's got a nice physique on him," Johnson says of Mtsweni.
"There will be a club announcement regarding a lot of things before the end of the week."