In addition, three members of first-team staff also returned positive tests for the virus, which has caused a global pandemic, infecting more than 40 million worldwide and costing over 1m lives.
Several high-profile footballers have caught the virus, perhaps most notably Juventus ace Cristiano Ronaldo, and on Monday it was confirmed the Milan pair were added to that growing list.
“AC Milan can announce that results determined from a series of swab tests conducted yesterday evening have returned from a laboratory with positive indications of Covid-19 for Gianluigi Donnarumma, Jens Petter Hauge and three other staff members," a statement on their official website reads.
“Whilst they are all asymptomatic, they have immediately entered isolation in their homes and the relevant local health authorities have been informed.
“Today, the players and staff were tested again for Covid-19, as is required by protocol, and there have been no other positive test results for the virus.”
The news comes as a blow to the Rossoneri, who have made an express start to their season and are due to face Roma in a Serie A encounter on Monday.
Stefano Pioli’s side currently lie top of Italy’s top flight, having won all four of their fixtures to date and having conceded just a single goal in their matches.
Furthermore, they have made a promising start to the Europa League group stage campaign, easing past Scottish champions Celtic 3-1 in their opening match of the competition, having qualified for it thanks to a thrilling 9-8 penalty win away to Rio Ave.
This is not the first time that the Milan squad has been touched by the virus. Striker Zlatan Ibrahimovic and defender Leo Duarte have both returned positive tests previously.
Indeed, the Swede took to Twitter to joke: “I tested negative to Covid yesterday and positive today. No symptoms whatsoever. Covid had the courage to challenge me. Bad idea.”
Donnarumma has been ever-present for Milan so far this season and his absence will open the door for summer signing Ciprian Tatarusanu to feature, while Hauge has made a strong impression after signing from Bodo/Glimt, returning one goal from three matches.