"Seriously", the 100m and 200m world record holder added. "That's the tough world of professional football", Beretta then said.
Bolt is now on trial at the Central Coast Mariners and scored his first two goals for the A-League side last week.
"I don't want to make a big fuss, I want him to sign the contract, get on the flight, arrive in Malta and train, because we need to prepare for the Super Cup".
Usain Bolt has been through plenty of drug tests in his time but he was baffled by the most recent request for samples of his blood and urine.
The 100 and 200 metre world record holder quit athletics past year and is now on trial with Australian football club Central Coast Mariners as he looks to achieve his new dream of becoming a professional footballer.
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Their legislation defines an athlete as a "person who competes in sport" if "the sport has an anti-doping policy".
The Jamaican, who previously trained with Absa Premiership side Mamelodi Sundowns as well as Bundesliga club Borussia Dortmund, has made no secret of his aspirations to play professional football.
Bolt - an eight-time Olympic gold medallist - has played a handful of pre-season games for the Central Coast Mariners as he chases a new career.
Bolt's agent in Australia, Tony Rallis, had also confirmed the approach, ESPN said.
He said he would like to stay with the club, especially after they gave him the chance to show his worth in the friendly with Macarthur South West United.