Finding a replacement for CR7 could be impossible but fans must trust Sir Alex, insists the former United legend...
The Portuguese international will leave Old Trafford this summer and join Real Madrid, after signing a six-year deal with the Spanish side.
Whilst the Red Devils now have £80 million with which to replace their No. 7, Robson has insisted Sir Alex Ferguson may need to bring in a couple of players.
“The one thing everyone has to realise is that United are not going to replace Ronaldo. He's a one-off,” Robson told the Sunday Mirror.
“[Antonio] Valencia is a good winger but he's not going to score the goals Ronaldo did.
“It wouldn't surprise me if the boss brought in another winger, even if he got Valencia.”
Yet whilst Robson admits Ronaldo will be missed, he also tipped Wayne Rooney and Dimitar Berbatov to shine in his absence.
“That would leave Wayne Rooney free to play down the middle,” he explained.
“In fact, I can see Wayne and Dimitar Berbatov coming out of Ronaldo's shadow.”
The former midfielder also backed boss Sir Alex Ferguson to bring in the right players and urged the United faithful to be patient.
“People have got to give the boss time and the chance to get in the players he wants,” he added.
“Players have come and gone at United in the past but eventually the boss has got it right and he'll do so again. The fans must keep faith in him.
“You find most players and club officials are away in June and there's more movement in July. There's plenty of time to do business.”
Gill Clark, Goal.com