Johannesburg - England loosehead prop Joe Marler is set to start in the dead-rubber final Test against South Africa this Saturday after first-choice Mako Vunipola returned home.
An England Rugby statement said Vunipola, who started in the first two Tests, had quit the tour for "family reasons" as agreed before the team flew to South Africa.
Marler came off the bench as a second-half substitute for Vunipola during the losses in Johannesburg and Bloemfontein.
Another loosehead prop, Ellis Genge, will also miss the Cape Town Test as a training-ground injury has ruled him out.
Alec Hepburn from Exeter Chiefs has been called up to provide front-row cover as England seek to snap a six-match losing streak since February.
The dismal run began with a defeat by Scotland in Edinburgh and other Test losses were inflicted by France, Ireland and South Africa (twice).
England conceded 63 points when beaten by the Barbarians in a warm-up game for the South Africa tour.