Wales announced last week that Welsh number two and United's former youth coach had retired from his international post.
"Mark has a very, very bright future," Eric told M.E.N. Sport.
"I could sense from the first time I saw him take a team talk against Belarus in 2000 that he had a lot to offer. He had the players' attention right from his first words and that wasn't just because he was a respected famous player. It was because the Welsh lads could see that his preparation work had been so well researched and he knew what he was talking about.
"There was an aura about him. I have always said that the most successful managers have an aura about them and I felt Mark had it as soon as I worked with him. It would be a massive blow to the Welsh if it ever happened that Mark moved into club management but, although I have never discussed it with him, I am sure that would be the next step and I would put money on him succeeding.
"I wouldn't have guessed that it would be in Mark's make up to go into coaching and management. I never saw evidence of it when I knew him as a player. With players like Bryan Robson and Steve Bruce you were absolutely certain that would be the direction they went in but it was never obvious with Mark. Nevertheless, he has a great future ahead of him."