Bolt, 31, is set for a six-week trial with the Mariners starting next month, with a season-long deal on the table should he make the grade.
"The deal between the Mariners and Usain Bolt in principle has been agreed, subject to a couple of benchmarks," local football agent Tony Rallis told the Big Sports Breakfast on Tuesday.
"Mainly, a trial, and of course marquee funds support from the FFA.
"Once the FFA comes back and says that they'll be part of the process, we're going to the trial."
Bolt, a Manchester United fan who attended the FIFA World Cup final in Moscow, retired from the track after the world championships in London last year.
He has since trialled with German giants Borussia Dortmund and Stromsgodset in Norway.
"If he's competitive, he will lift our A-League profile," Rallis said. "He will create dreams for young people and he will give the A-League a profile no amount of money can buy.
"This bloke's an ambitious athlete. The A-League needed a hero, and we got superman.
"The owner of Central Coast Mariners has put his hand deep in his pocket and guaranteed 70 per cent of the salary."
The Mariners firmed as Bolt's most likely destination after taking the sprint king's ambitions seriously, despite interest from several A-League clubs.
Mariners chief executive Shaun Mielekamp said there was still a lot of work to do on the "surreal" deal, and noted the trial period was extremely important to see Bolt's skill level.
"It would only be big if he can play and if he can go really, really well," Mielekamp told the Seven Network.
"Because if he comes and he's not up to the level then it actually has a detrimental effect.
"But if he comes and he's as good as our reports are saying that he can be, then that would be very exciting and I'm sure that this stadium would be pretty full every time we put the boots on."
Mielekamp said Bolt was known to improve significantly every time he trained, and was an extremely fast learner.
"He's got a very good left foot and only time will tell what level he's at, and does that fit the A-League," he added.
An attempt to contact Bolt's agent Ricky Simms has been made.
An eight-time Olympic gold medalist, the Jamaican sprinter is still the world record holder in the 100 metres, 200 metres and 4 × 100 metres relay. He won the gold medal in all of these events at the three past Olympic Games and he is widely considered to be the greatest sprinter of all time.
Bolt won the 100 m, 200 m and 4 × 100 m relay at three consecutive Olympic Games, although he lost the 2008 relay gold medal about nine years after the fact due to a teammate's doping disqualification.
An eleven-time World Champion, he won consecutive World Championship 100 m, 200 m and 4 × 100 metres relay gold medals from 2009 to 2015, with the exception of a 100 m false start in 2011.
