Back resigned from his head coach position at Leeds as the Yorkshire side were relegated to the Championship at the end of the season but he had been expected to return to top-flight coaching in the near future.
Instead the World Cup winning triple Lions tourist has joined forces with businessman Michael Aland whose vision is to bring Premiership status, and a 30,000 seater stadium complete with retractable roof, to the town where our sport was invented.
"This is an incredible challenge and one which, after a great deal of thought, I felt I could not turn down," said Back.
"I received an approach from Michael in May, less than an hour after my resignation from Leeds.
"He sold me his vision of taking this club to the top flight of English rugby, while doing something really meaningful for the town."
Back, who previously told this site that he would love to be involved with coaching the Lions, doesn't believe the move is a backward step, although it is hard to agree in the short-term.
The 42-year-old insists he is committed to Aland's long-term aspirations and that successfully achieving those targets would be a major boost to his coaching CV.
"It's a big call for me having coached in the Premiership and I have asked myself whether it's a retrograde step given how ambitious I am," added Back, who is the oldest Test Lion in history.
"But it's not about money. Nor is this an easy option by any stretch of the imagination, which is why I asked for a five-year contract.
"I believe that turning around Rugby and getting the club to the Premiership would be a significant achievement and one I can use as a stepping stone to coaching at the very highest level."