Van Niekerk has now linked up with his new coach, Lance Brauman.
After he left Botha's camp, van Niekerk had been training in South Africa and competed in the national championships in April while he waited for visa approval from the American authorities.
At the championships in Pretoria, van Niekerk won the 200m. However, the delay in paperwork regarding his visa meant he did not travel with South Africa's team to the World Athletics Relays in Poland.
Writing on social media in February, van Niekerk explained his reasons for leaving Botha, who he had trained under nearly his entire career.
"As much as I have enjoyed my experience with Tannie Ans and her group‚ I am hoping to break my world record and to do that I need to ensure I am training alongside the world’s best sprinters," he said then.
"I feel a temporary move to the US will be in my best interests for the immediate future. I look forward to working with my new coach and training partners‚ and I hope to continue carrying the SA flag with pride at international level."
Van Niekerk's future
Miller-Uibo shared a photo of herself with van Niekerk on social media, welcoming him to the training team.
"When you get blessed with a world record holder as a training partner!" wrote Miller-Uibo.
It is unclear what van Niekerk's next competition will be for now. He is still yet to meet the qualifying mark for the Tokyo Olympics in either the 200m (20.24s) or 400m (44.90s).