"He's also proud of the support he's received from his club but also from the whole football world," Pioli told his press conference on the eve of Milan's home game with Bologna on Saturday. "He has trained very well this week."
Last Sunday, at Udinese, fans racially abused the France goalkeeper.
Maignan walked off the pitch, followed by his teammates. The match resumed after a five-minute suspension and Milan went on to win 3-2.
Udinese were ordered to play one match behind closed doors, against Monza on February 3rd, but have said they will appeal. They also banned for life five fans identified as having abused Maignan.
"Udinese behaved impeccably in handling the situation and the sanctions," said Pioli.
"Ninety-nine-point-nine percent of people go to the stadium to experience a moment of sport, to exult, to encourage the players and to show passion. But there are things that cannot be accepted, and the reactions were the right ones on the part of our club and everyone. We had to react firmly."
Udinese coach Gabriele Cioffi expressed his support for Maignan but criticised the punishment as he spoke ahead of his team's visit to Atalanta on Saturday.
He said the stadium ban was "something extremely heavy for a city and a club that are exemplary in terms of integration".
"We were all shocked and hurt by what happened to Maignan," he said.
"But if it only takes five people, who were not acting together, in a stadium to receive such a punishment, it becomes a problem."
He added: "These types of behaviour must be condemned, but neither the team nor the club had anything to do with it. And next week, we'll be playing an important match with an incredible penalty."
