The eight-time Olympic gold medallist, who retired from athletics in August last year, is to train with the Bundesliga side in March.
But the 31-year-old still retains the hope of playing for the club he cherishes and says he has spoken to Sir Alex Ferguson about a move.
"In March we're going to do a trials with Dortmund and that will determine what I do with that career, which way it goes," he told the Daily Express.
"If they say I'm good, and that I need a bit of training, I'll do it.
"It makes me nervous. I don't get nervous but this is different – this is football now.
"It'll take time to adjust but once I play a few times I'll get used to it. It was the same when I started track and field. I was nervous for a while until I started getting used to the crowd, people and everyone around and it falls into place.
"One of my biggest dreams is to sign for Manchester United. If Dortmund say I'm good enough, I'll crack on and train hard. I've spoken to Alex Ferguson and I told him he needs to put in a good word. He told me if I get fit and ready, he will see what he can do."
Bolt is adamant he has what it takes to become a Premier League footballer despite having no professional experience in the game.
He added: "I watch a lot of football, I understand it, I play it. With training, I could be good. Me and [Paul] Pogba talk a lot. I watch and ask him a lot of questions. I want to play but it has to be in the top league. I'm not content to be average.
"I strive to be the best and if I get a chance to play for a team like Manchester United it will be a massive deal."
