Former Sunderland chairman Niall Quinn has questioned whether Manchester United should move for Real Madrid star Cristiano Ronaldo.
Quinn has offered a word of warning about any potential Old Trafford return.
"There is a risk. The commercial guys would love it but I think his longevity - staying at the top of his game for as long as possible - would be better served by staying at Real Madrid," he told Sky Sports.
"If he comes to United, he's putting everything at risk. Stats will tell you, doing it for a second time at a club is difficult."
