Donnarumma enraged Milan supporters when he left as a free agent just over two years ago, costing the seven-time European champions a hefty transfer fee for a goalkeeper considered at the time one of the best, if not the best, in the world.
Milan have lost other players in that manner over the past few seasons, including Serie A title-winning midfielder Franck Kessie, but Donnarumma hurt the most.
The Italy 'keeper signed for Milan as a 14-year-old, became a first-team player at 16 and had repeatedly professed his love for the club, making supporters believe that he would remain a fixture in the way Gianluigi Buffon had at Juventus.
Instead he refused to bend on wage demands over months of talks and walked away, replaced by PSG academy product Mike Maignan who was crucial to Milan claiming their first title in 11 years in 2022.
However, Maignan's superb performances between the sticks did not do anything to dull the anger of the betrayal, while Donnarumma has failed to convince fans in Paris where he moved after starring in Italy's European Championship triumph.
"It's tough but you need to distance yourself from it," said Donnarumma to Mediaset last month, talking about criticism.
"We're all human, obviously you read things on social media, but you need to distance yourself from it.
"Mistakes happen, we're not robots but the important thing is to work hard and push forward with the team."
Milan under pressure
Donnarumma was inundated with boos and whistles on all three occasions he has played at the San Siro with Italy in the last two years, Milan fans in the crowd making their feelings very clear and leaving no doubt of the reception he would receive should PSG ever come to town.
Last week Milan's hardcore supporters hinted at the welcome they would give Donnarumma when he takes the field at the San Siro, publishing on their Instagram page a picture of boxes containing material for a pre-match display which will almost certainly be aimed at the 24-year-old.
An emotional night for Milan fans comes with the team at low ebb, with coach Stefano Pioli and the team booed off the field after Saturday's 1-0 defeat to Udinese which left them six points behind Serie A leaders Inter Milan.
"I have everything I need to do a good job and if the results don't come then it's my fault," said Pioli after Saturday's loss.
"I'll work on how we play, but we can't perform how we did against Udinese."
Pioli's team are yet to score a single goal in their Champions League campaign and have won just one of their last six matches in all competitions since the start of October, with three defeats in that period including last month's 3-0 hammering at the Parc des Princes.
However, despite being bottom of Group F Milan can still qualify for the last 16 as two points separate them from second-placed Dortmund who host Newcastle in one of Tuesday's two early matches.
Pioli is sweating on the condition of France full-back Theo Hernandez and starting right winger Christian Pulisic, although both should be fit to play unlike Rade Krunic who is out with a thigh injury.
But the paucity of Milan's play in recent weeks and the prospect of a wobbling defence facing Kylian Mbappe has AC fans fearing the last laugh will be for Donnarumma.
