Ntuli returned to South Africa earlier this month after a trial at Swedish club Djurgardens failed to yield a move for the 27-year-old.
According to a source close to Ntuli, Sundowns and Usuthu are now in advanced negotiations over the ex-Golden Arrows forward's services.
"Both Sundowns and AmaZulu are talking," says the source.
"The move is likely to happen any time this week."
The KwaZulu-Natal born hitman, who spent the past three seasons out on loan to Platinum Stars (now called Cape Umoya United), was linked with Usuthu, Chippa United and Maritzburg United prior to flying to Scandinavia.
Ntuli had a productive six-month loan spell at AmaZulu in 2015 before he linked up with Dikwena.
The Durban-based outfit currently have Argentine newcomer Emiliano Tade and veteran duo Mabhuti Khenyeza and Siyabonga Nomvethe as some of their options upfront.