"He was going to go back to America,'' Blackburn manager Steve Kean said. "He had an offer to go back there and be a player-coach.
"He was very excited about it and then, at the last minute, Tottenham came in and offered him a short-term until the end of the season. He was a fabulous servant to the club.''
Nelsen has signed a six-month deal with Spurs with an option for another year. It was the prospect of playing for a top-four side that attracted him the most.
"Medals, trophies are things you strive for,'' he told TV3. "Blackburn got to five semis in my time and never made a final, so it's very exciting.''
He's bound to get game time as Spurs, currently third on the Premier League table, attempt to keep pace with the two Manchesters (City and United) and they also have a great chance to progress further in the FA Cup after being drawn against League One outfit Stevenage in the fifth round.
But he wants to force his way into the starting side and knows he has a challenge on his hands with Michael Dawson, Ledley King and Younes Kaboul, as well as the injured William Gallas, on Spurs' books.
"I kind of like when the odds are stacked against you, so we'll see,'' he said. "We'll get out there and give it everything.
"It feels like you're going back to the first day of school, so yeah, everyone will be looking at you and judging you so I better clean my boots and comb my hair... it'll be fun.''