Du Toit is returning to Cape Town for the birth of his first child while a calf injury has ruled Etzebeth out of Friday's match against the Queensland Reds in Brisbane and the April 12 clash at the Melbourne Rebels.
Etzebeth was hurt in Saturday's 24-9 loss to the Auckland Blues in New Zealand.
Also out is centre Dan du Plessis, who limped off with a knee injury after just 10 minutes at the weekend, and is headed back to Cape Town.
But prop Wilco Louw is staying with the tour party as his ankle injury is being assessed before a decision is made on his availability for Friday's match.
Wing Seabelo Senatla and utility forwards Johan du Toit and Ernst van Rhyn left on Monday for Australia to reinforce the squad, the Stormers added.
(Reporting by Mark Gleeson; Editing by Christian Radnedge)
