Speaking to Viacom18 Sports, Wayne Rooney said: "It's a shame because Cristiano Ronaldo has been a fantastic servant for Manchester United.
"I'm sure there'll be teams looking to sign him. Certainly, if he has a good World Cup tournament, there'll be a lot of teams looking to try and sign him.
"I have said many times that Ronaldo is one of the best players of all time. It's sad to see it end this way, but I think there was no option.
"He is now 37. I still felt there was a part for him to play at Man United maybe not from the start but coming on. He obviously doesn't feel to accept that role.
"He wants to continue his career elsewhere, so for the club, it's probably the best thing. It allows them to focus on the players who are there and want to be there."
Ronaldo's Man United exit was made official earlier this month with the 37-year-old leaving the club 'by mutual consent' after his explosive interview with British TV presenter Piers Morgan.
The Portuguese will be a free agent when the January transfer window reopens and there's a possibility of him staying in the Premier League with Newcastle and Chelsea reportedly showing interest.
