Giggs has on Friday signed a new one-year contract extension that will take his United career into an incredible 23rd season.
It also means he will still be at Old Trafford beyond a birthday milestone where the vast majority of footballers have found something else to do.
"Ryan is a one-off," said Carrick.
"Not many people have lasted as long as Ryan.
"It is not just that he is still playing, it is the way he has adapted his game. To be able to do that can't be easy.
"You have to take it year by year and see how your legs hold up.
"But going on for that long is is a hard thing to do."
Giggs has benefited from regular yoga sessions during the latter years of his career.
In addition, a naturally slim physique has helped, as has a well-balanced diet.
"Ryan sets the example on and off the pitch - and has done for a number of years," said Carrick.
"He also sets the tone around the dressing room. He doesn't say an awful lot but when he does speak, everyone listens and everyone respects him.
"He is Mr Manchester United."
Sir Alex Ferguson has also confirmed Giggs will make the 1,000th senior appearance of his career either against Norwich at Old Trafford tomorrow or that mouth-watering Champions League encounter with Real Madrid on Tuesday.
Even Ferguson has described Saturday's game as "mundane", although he has assured United fans his players will be fully focussed on opponents who inflicted the last league defeat on his team in November, 15 games ago.
"Norwich have played in spells, especially this season," said Carrick.
"They had a slow spell, then a really good one when they beat us. After that they came off it a little bit, then they had a good win against Everton last week.
"They are a tough team to play against, really solid and well organised, who put a lot of crosses into the box and make you defend.
"We will have to be at our best to get the three points."