The Italian side are close to bringing in the 21-year-old and his representative has no doubt he will play a leading role at San Siro.
Brahim Diaz's agent Pedro Gonzalez says Real Madrid failed to get the most out of the young midfielder and has backed his client to succeed on loan at AC Milan.
The 21-year-old joined Madrid in January 2019 after six years at Manchester City but has made just five La Liga starts since, making only substitute appearances in the top-flight last season.
He previously vowed to win over head coach Zinedine Zidane, but the Spaniard is now on the verge of linking up with Milan for the 2020-21 season after flying into Malpensa airport on Wednesday.
Diaz declared himself "ready for this challenge" ahead of undergoing a medical and his representative Gonzalez is confident the ex-Man City product can become a key player at San Siro, having been underused by Zidane at Madrid.
"Brahim returned to Spain in January 2019, but in Madrid they didn't give him the required space and above all the confidence he needed," he told Tuttomercatoweb . "He's a young player and he needs to play continuously to bring out his full potential.
"I'm convinced of the Rossoneri's choice. Brahim has already lived abroad and will therefore adapt quickly to his new reality.
"His future team-mate Samu Castillejo, another great player I brought to Malaga, will help him. I say this with great pride.
"If Brahim Diaz has chosen Milan, it means he already knows he can help the team by carving out a leading role. I have no doubts about this. As soon as he has finished his growth path, we will talk about an absolute champion and not a promising youngster anymore."
Spain Under-21s international Diaz has scored two goals in 21 appearances for Madrid in all competitions during his 20 months at the club.
He is set to be the second young Real Madrid midfielder to leave the club on loan this week, with Dani Ceballos about to re-join Arsenal for a second season.
The Spain international spent the 2019-20 campaign on loan in north London and enjoyed a fine end to the season, helping Mikel Arteta’s side claim a record-setting 14th FA Cup.
Goal confirmed reports in Spain that another loan deal is close to being agreed , with Arsenal and Real Madrid deep in discussions over a deal which will see the 24-year-old spend the 2020-21 campaign with Arteta’s side.