Manchester United Transfer News: Cristiano Ronaldo Agent Dashes Return Rumours

Any Manchester United fans still clinging on to the hope that Cristiano Ronaldo may one day return to Old Trafford are likely to be disappointed after his agent suggested the Portuguese superstar will end his career at Real Madrid.

Jorge Mendes believes that recent Ballon d'Or winner Ronaldo will play on into his late 30s, continuing at the club he joined from United for £80 million in 2009, per Marca:

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I'm convinced [Ronaldo] will retire at Real Madrid. I'm almost certain he'll retire at 38 or 39, because he's got a lot of years in him yet. We all know he's a total professional, the kind of person that really looks after himself.

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Rumours have been ongoing that Ronaldo may one day return to Old Trafford, with the player himself increasing such talk back in September, per B/R UK:

However, it certainly seems an unlikely switch, considering Los Blancos are the current European champions while the Red Devils continue to struggle in the Premier League following the 2013 retirement of Sir Alex Ferguson.

Equally, the 29-year-old continues to thrive at the Bernabeu. So far this season, he has bagged an extraordinary 28 goals in 17 La Liga appearances, per WhoScored.com. 

Ronaldo picked up his third Ballon d'Or award earlier this month and will likely be in the running for a fourth in a year's time as he continues to pursue individual, as well as team, success, per ESPN FC's Rob Train.

It does seem unlikely that the former Sporting star would depart such a fantastic Real team, as he continues to perform extraordinary feats for Los Blancos.

Mendes' stated belief that Ronaldo can continue for another nine or 10 years is certainly a possibility, considering the player's phenomenal work ethic, although he surely can't stay at his current level for that long. 

Ronaldo turns 30 in February, and his pace and physicality are a huge part of his game, both of which are sure to decline with age, per football writer Miguel Delaney:

However, he certainly doesn't look to be on the wane just yet and is currently the best player on the planet playing for one of the best teams.

Mendes no doubt knows better than most what Ronaldo's future plans are, and it seems they lie in Madrid, to the likely distress of many United fans.