The claim comes as Donnarumma's future remains unsure, despite the young goalkeeper signing a new contract last season after long negotiations.
Agent Raiola made the surprising comment during a Football Leader conference today.
“It’s important to respect the fans, especially the intelligent ones. Donnarumma could stay at Milan for life, that’s what the fans have always asked for.”
The comment was even more surprising given Raiola had been the driving force towards trying to sell Donnarumma to clubs such as Real Madrid, Paris Saint-Germain and Manchester United in recent seasons.
As such, he was asked if this was an ironic dig towards Milan owner Yonghong Li.
He replied: “I don’t know the meaning of irony… I will say it’s more likely we’ll see the Chinese leave than him…”
There was some evidence behind the claim, though, with recent reports suggesting none of the interested clubs were willing to pay Donnarumma's £70m asking price.
Donnarumma has played 106 times for AC Milan in Serie A since making his debut as a 16-year-old.
This season, the Italian featured 38 times in the league, conceding just 42 goals and keeping 12 clean sheets. He made a further 15 appearances in other competitions - with another nine clean sheets.
The now 19-year-old goalkeeper graduated through the Rossoneri academy setup after transferring to the club as a 14-year-old from Napoli's youth team.
Donnarumma also has six caps for Italy - after becoming the country's youngest debutant at 17-years-old - taking over the reigns from legend Gianluigi Buffon.