The experienced goalkeeper has picked up a hamstring problem in last weekend's derby and will consequently be out of action for the remainder of the current campaign
The shot-stopper sustained a hamstring injury in Milan's 4-2 league loss against Inter on Sunday, and was forced to leave the pitch after 35 minutes of play due to the knock.
Abbiati underwent further examination on Wednesday to determine the extent of the injury, and Milan have now announced on their official website that the 34-year-old has a tear in his right hamstring.
It's not yet exactly known how long Abbiati will be out of action, but the glovesman will not feature in Milan's final league game of the season.
Meanwhile, Daniele Bonera has been diagnosed with a tear in his left calf.
The defender also picked up the injury in Milan's 4-2 loss against arch-rivals Inter and faces an undetermined spell on the sidelines.