The 37-year-old former Manchester United forward has played for nine clubs over a 20-year period but is reaching the end of his career in football.
He told the Mirror: "I think being a coach is very stressful. One year is like ten years.
"I see many coaches - first season, they have black hair, next season they have grey hair.
"I think as an active player that when you become coach, you know the game from inside of the field.
"And suddenly, you are standing on the outside and coaching the players to do. And you know, deep inside, I would do it better. It's a tricky thing.
"I don't say no because you never know what happens but… I don't think so."