South Africa forward Duane Vermeulen says Billy Vunipola will be a 'big loss' for England as the Springboks ramp up the pressure on Eddie Jones' side.
The Saracens No. 8 has returned home after re-fracturing his arm during Saturday's second Test in Bloemfontein -- the latest in a series of injuries that have set back his international career.
England lost the match 23-12 and with it the series as they fell to a sixth Test defeat in a row -- their worst run since 2006.
They will be desperately aiming to avoid a whitewash in the third and final Test in Cape Town Saturday but Springboks No. 8 Vermeulen believes they will be a different team without Vunipola.
"He's definitely England's go-forward guy and without him, from what I saw in the Six Nations they struggled. They need that guy," Vermeulen said.
"Hopefully Nathan Hughes can step up and make it his own. Billy is a big loss."
Vunipola's brother Mako has also returned home for family reasons in an arrangement agreed with team management before the tour.
Both players are further important losses for head coach Eddie Jones who decried the thinness of his squad in the wake of Saturday's loss, saying there were 25 players sitting at home and unavailable for selection.
But Vermeulen says South Africa remain aware of the threat England can pose.
"If we can win 3-0 then we want to do that. We would like to go for the three-match clincher," he said.
"England are not far off -- maybe with one or two tweaks they will bounce back. They are still one of the best teams in the world. You have to respect them."