Sir Clive Woodward believes Lawrence Dallaglio should be part of England's World Cup defence, if he is fit.
Dallaglio starred in Wasps' Heineken Cup final victory
The former captain was included in coach Brian Ashton's World Cup training squad after leading Wasps to victory in the Heineken Cup.
"I would play Dallaglio, no doubt, as long as he's fit," said Woodward, England's World Cup-winning coach.
"If South Africa know Dallaglio is playing, it may put doubts in their mind. They don't want to see him."
Dallaglio has not played for England since the 2006 Six Nations and his last Test start was on the summer tour of New Zealand and Australia in 2004.
If England win against South Africa in Paris, they can go all the way
The 34-year-old is part of a 47-man training squad that will be cut to 30 on 14 August.
But Woodward, now the elite performance director of the British Olympic Association, told the BBC that his experience will be vital for England.
"It's good they are bringing back some experienced players, the World Cup is not the time to blood new players - and I've always thought we've got the players," he said.
"If they can get their best 15 they can cause an upset. They can do this if they get their right team on the field.
"If they win against South Africa in Paris, they can go all the way. Whoever wins that game has got a very good chance in the final."
Woodward's sentiments echo those of another former England coach Andy Robinson.
"When Lawrence gets right on top of his game there is no better number eight in the world," Robinson told BBC Five Live's Sportsweek programme.
"He's a player you need in the squad. He will bind the other 29 together."
He should have the chance to prove his worth in warm-up games against Wales (4 August) and France (11 and 18 August).
Now he's made this squad, it says to me Brian sees him as an integral part of that World Cup
England open their campaign against USA on 8 September, with tough group matches against South Africa and Samoa to follow.
Robinson said of Dallaglio: "There are a number of things that he brings but first and foremost are his performances.
"His performance in the European Cup final was superb and I think the stage is set for him.
"The other aspect is the physicality he generates in the others. With the commitment he demands other players raise their game.
"When you play against South Africa you're going to need that level of physicality."
Dallaglio's former team-mate Matt Dawson also thinks head coach Brian Ashton will include the 34-year-old number eight.
Dawson told Five Live there is no point including the Wasps forward in a 47-man training squad only to drop him at a later date.
"What's there to learn about Lawrence Dallaglio? He has proven that under pressure he can perform and lead a side," he said.
"Now he's made this squad, it says to me Brian sees him as an integral part of that World Cup 30 come September."