South Africa’s Duane Vermeulen has claimed that England have “struggled without Billy Vunipola in the past.
The Saracens forward has returned home from England’s tour against the Spingboks after fracturing the arm he broke at the start of the year and now he faces another lengthy period away from the game.
England have already lost the three-match series ahead of their final match in Cape Town on Saturday and Vermeulen believes Eddie Jones’ men are not the same team when Vunipola is absent.
"I saw Billy go down and thought it was his shoulder at first," said Vermeulen.
"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.
"Hopefully Nathan Hughes can step up and make it his own. Billy is a big loss."
England have lost five Test matches on the spin and South Africa could inflict a 3-0 whitewash on the tourists at Newlands this weekend.
"We don't know what team Rassie will pick, but if we can win 3-0 then we want to do that. We would like to go for the three-match clincher," Vermeulen added.
"England aren't 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.
"They are going through a tough patch but all teams go through it. I know they will bounce back."