Alan Hansen insists Wayne Rooney's fitness is of "mega" importance to England and Manchester United.
The striker suffered an ankle injury during the Champions League quarter-final first leg defeat by Bayern Munich in Germany on Tuesday night. Rooney is due to have a scan on the problem with followers of the national side and United holding their breath, hoping it is not too serious.
Asked about how important Rooney's fitness is to country and club, former Liverpool defender and Match of the Day pundit Hansen stated: "It is mega. The way Rooney has played all season, everyone's right when they say he has reached another level."
He added: "He has not just the talent, the ability and the quality but the other attributes that set him apart.
"That's the enthusiasm, the energy and the willingness to win, where he hates getting beaten.
"It is a sign of all the great players that in the final third of the pitch when they are maybe not having such a great night they will give you something extra.
"He demands a lot of himself as well and his colleagues. For Manchester United and England he is key.
"He is key to United in the Premiership and Champions League and key to England doing well in the World Cup."
England 1966 World Cup winner Roger Hunt agrees with Hansen that England badly need Rooney on board when they go to South Africa in the summer.
Hunt said: "Rooney has improved this season, especially his heading ability. He is also getting into the danger areas, rather than chasing back and wasting his energy. It is so important for Rooney to be playing for England. There are other players who can come in of course but Rooney has become the talisman. With him in the team England will have more of a chance."
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