Rovers had welcomed applications for the role that had been left by Dean Saunders, who had recently opted to take charge of Championship outfit Wolverhampton Wanderers.
Youngster Mac Wilson took up that invitation and managed to impress Ryan with the content of his application.
"My daughter Claire was with me at the time that I got Mac's letter and my first thought was to give him a ring. I got his dad on the phone and asked if I could speak to Mac with regards to the vacancy at Rovers," Ryan told the Doncaster Free Press.
"He came on the phone and I asked him whether he would like to come down for an interview. I invited them both down on Saturday for a look round, meet the players and to give him an interview.
"Mac actually put in his letter that he will get us in the Premier League in three years. I thought that was a very positive statement."
The job has since been given to Bryan Flynn until the end of the season.