Manchester United are said to be one of the clubs interested in the Italian.
Donnarumma, 18, has risen through the AC Milan ranks and is now a regular for the San Siro giants.
His prowess has seen him called up to the Italy national side and tipped to be the long-term successor to Gianluigi Buffon.
Milan are desperate to keep Donnarumma but admitted recently the decision over his future rests with the player and his agent.
And Raiola revealed to Italian newspaper Corriere dello Sport that clubs are queueing up to secure a deal.
“Gigio is the Maradona of goalkeepers,” Raiola said.
“He can only grow and he has to be left alone to grow in peace. He’s not a slave, nor a robot.
“There are 11 top clubs which are interested in him.”
Manchester United are said to be keen on landing Donnarumma as uncertainly persists over David de Gea’s future.
Real Madrid want to sign De Gea but United have reportedly rejected a £60million offer.
The Spain international is open to joining the Bernabeu club but is contracted to United until 2019.
As for Donnarumma, Inter Milan and Juventus have also been linked with the teenage sensation.
Manchester City were also linked with a move for the Italian but have instead turned to Brazilian goalkeeper Ederson, who is expected to complete his £34.9m move from Benfica soon.
AC Milan do not want to sell to a rival and Raiola admits a transfer this summer is far from being completed.
“The concept is clear. When there’s a question to be resolved, in the Netherlands we say: ‘we’re talking about the elephant in the room’. Let’s talk about it,” Raiola added.
“I’ve never said to (directors) Marco Fassano and Massimiliano Mirabelli: ‘he’ll sign now’ or ‘he won’t sign at all’.
“I understand the stress and the expectations of the fans, Gigio is already a symbol for the club and for the new owners it would be ideal to seal a renewal today. Yesterday, in fact.
“But Fassone and Mirabelli only took office just over a month ago. Leave us to work in peace.
“I assume all the responsibility for the definitive choice we’ll make.
“If you ask me: ‘is there a chance Donnarumma will sign with Milan again?’ then the answer is yes.
“If you ask me: ‘is there a chance Donnarumma will leave Milan?’ the answer is yes.”
