Mercer was critically injured when an official course car slammed into him as he made his way back to the Grandstand against the racing direction of the TT course, after being instructed to do so by a marshal.
The course vehicle was making its way to the scene of a fatal accident that claimed the life of Manx rider Dan Kneen.
Mercer is still receiving treatment and in a rehabilitation centre for limb and spinal injuries and admits there is a possibility he could lose a leg.
However, the 37-year-old has not been put off the idea of racing again in the future.
“How no one got killed is a miracle,” said Mercer, who has not been permitted to see the official report into the collision.
“I remember seeing the car, it was flying, and then I remember waking up five days later. That’s about it really.”
He went on: “I’ve got spinal cord issues. I’m in a wheelchair, I can’t stand up and I can’t walk. It’s very difficult. It’s a really slow slog.”
In an interview first published by the Manx Examiner, Mercer added: “I would love to race again – but it won’t be tomorrow. I will definitely ride a bike again. It’s my dream to ride a bike again – you’ve got to have goals.
“There are things I still want to achieve in life. It can’t end like this.”
An independent investigation was carried out by race organisers the Auto Cycle Union (ACU) into the incident, headed by lawyer Rob Jones – a former chief executive of the UK Motor Sports Association
The ACU has said the report was a ‘privileged document for legal reasons’ and that the recommendations made by Mr Jones were being put in place where appropriate.
These include the continuation of a ban on competitors travelling against the racing direction of the TT course and a review of marshal training along with additional training for members of race control.
Mr Jones’ report also suggested course cars and the motorcycles of travelling marshals should be fitted with tracking devices.