Parker hails Giggs coaching appointment at Man Utd
Parker believes Giggs will have "frightening" knowledge from all his years in the game which the club can use to its advantage.
The former England defender, 49, said: "Maybe this move goes beyond playing and is also about using his experience.
"As a player, Ryan is a threat - we all know he will be of great use in the squad - but he is also a threat with his knowledge of the Premier League.
"He will go on and on and that is a frightening thought for the rest of the Premier League. He simply has to be there - and for a very long time.
"Certain things happen where people come in and do it their own way. But the Manchester United way is proven, there is a method to how it works.
"You can see that David Moyes respects that, with Phil Neville, Paul Scholes and Nicky Butt all back there in coaching roles now."