Coach Vincenzo Montella said he is confident teenaged goalkeeping sensation Gianluigi Donnarumma will pledge his future to AC Milan amid his agent's claims he should be "in a bigger shop window".

Milan host Lazio Tuesday for the first of three games in 10 days that could test their resolve to battle for a place in Europe this season, and preparations have been disrupted by uncertainty surrounding Donnarumma.

The 17-year-old 'keeper is represented by Mino Raiola, the Dutch 'super agent' who boasts Paul Pogba, Mario Balotelli and Zlatan Ibrahimovic among his clients.

Raiola once famously compared Donnarumma to a masterpiece by the Italian artist Amedeo Modigliani, insisting the Naples-born shot-stopper is worth a mind-blowing 170m euros.

In an interview with Rai, the Italian-born Dutch football agent appeared to up the stakes further when he hinted Donnarumma should move to a bigger club because: "Gianluigi is a rare jewel, and rare jewels should be displayed in the most beautiful window. Otherwise, what kind of jewel is he?"

Donnarumma won't be showcasing his talents in the Champions League or its poorer cousin the Europa League because Milan failed to qualify for Europe this season.

But Montella believes the 'keeper, whose deal with Milan expires in 2018, will remain faithful to the Rossoneri cause.

"I'm sure Milan want to keep Donnarumma. Raiola is originally from the south (of Italy), like me and like Donnarumma so I'm sure he will sign the contract no matter what he (Raiola) says," Montella said Monday.

"I say that with a smile on my face because Mino is good at his job, the same as the club management at Milan."

As Milan near the completion of a takeover by a Chinese consortium at the end of the year, the seven-time European champions can ill afford to lose one of their top players.

At the age of 16 years and eight months, Donnarumma became the youngest goalkeeper to make his competitive debut in Serie A when he started in a 2-1 win over Sassuolo in October 2015.

Relegating experienced Spaniard Diego Lopez to the bench, Donnarumma has since become Milan's number one and the heir apparent to Italy and Juventus legend Gianluigi Buffon.

When Buffon's talent emerged at former UEFA Cup winners Parma, Juventus were quick to snap him up in 2001 and he has been with the Turin giants ever since.

Milan, who secured a precious 1-0 win at Sampdoria on Friday to move up to 10th at four points behind leaders Napoli, face a heavy schedule over the next 10 days beginning with Lazio at home on Tuesday.

"Lazio are on the up and easily adapt to the style of their rivals, plus they are dangerous in dead ball situations," added Montella, who as a player was a striker for Lazio's bitter city rivals Roma.

Montella could face a bigger test when the Rossoneri travel to his former club Fiorentina on Sunday.

A week later, Milan welcome high-flying Europa League debutants Sassuolo to the San Siro.