The Reds defender said: "He's a great player and I think he will be a big miss for the Premiership. He makes a big difference to Manchester United, even though they have a lot of other great players, and I think he was the one for them.
"But I'm sure Sir Alex Ferguson knows what he is doing and to have £80million to go and spend, that's a lot of money. It will be difficult to replace Cristiano Ronaldo, but maybe they will do it a different way and get two or three players.
"It's difficult to replace that, but I'm sure they will sort it out. Hopefully they won't bring in someone as good as Ronaldo!"