The Wolves manager brings his side to Old Trafford this evening to face a team that could contain a player McCarthy describes as "remarkable".
"I voted for him on Sunday night," he said. "I never usually vote on those things but I thought he deserved the accolade for what he has achieved in his career.
"I don’t think anyones needs to talk about how difficult it is to play at the top level for 20-odd years – just look at how few players have done it. There have been some really good players come and go during Sir Alex’s reign but Ryan has stayed the course."
McCarthy also had high praise for Paul Scholes, David Beckham and the Neville brothers.
"There are a few who came through with Ryan who have also stood the test of time. They’re all similar types and have had superb careers."
And while McCarthy says sports science and training methods have improved so much that it shouldn’t be considered unusual for somebody to spend 20 years at the top, he doubts many players possess Giggs’ burning desire to succeed.
"Careers should be able to be prolonged," he said. "Whether or not players have the desire to prolong them is another matter. You get to 32 or 33 and tackles start to hurt a little more and injuries take longer to heal.
"Ryan had a lot of injuries earlier in his career with his hamstrings and must have got as much money as he needs, but his desire to continue playing is remarkable."