Bolt, who won eight Olympic gold medals during his days on the track, is a massive Manchester United fan and has a long-standing ambition to play professional football.
The 32-year-old 100 meters world record holder and eight-time Olympic gold medal victor joined Central Coast on trial in August in a bid to win a contract.
However, it was Koch's next comments that have caused controversy.
Football agent Tony Rallis, instrumental in brokering the deal which brought Bolt to Gosford in August, was quoted as saying: "There is a club in Europe that has offered Bolt a two-year deal, they have been taken over by new owners who have aspirations of Champions League football". It's a free world.
Koch made the awkward joke during Tuesday morning's show after Bolt's expected transfer to a European club was mentioned.
"So the Mariners sell him for money, they make a lot of money out of it?"
Beretta replied: "It's a win-win". You sell him, so be it.
The 100-metre world record-holder scored his first two goals in professional football on Friday when he started a pre-season game against second-tier Macarthur South West United in Sydney.
A Mariners spokesman said there was no change in Bolt's position at the club, describing reports that he might quit his trial as "rumours".
"Who said slavery was over - anyway".
'Just watched 10 seconds of (Sunrise) and Kochie almost blurted out some kind of slavery joke?
'Did Koshie REALLY attempt to make a slavery joke, on the back of a Usain Bolt story?' one person tweeted.