AC Milan coach Massimiliano Allegri knows they face fan protests for this weekend's Trofeo TIM.
The Rossoneri will face Inter and Juventus in a mini-tournament at Bari's Stadio San Nicola.
"This is Year Zero for Milan," Coach Allegri told Sky Sport Italia.
"In all 12 champions have left, some due to their age and others because of decisions made by the club. We couldn't say no to PSG.
"We must work on the foundations, even if there are still many players who remained. There is a month left in the transfer market and last season the team really changed its identity right at the end of that window."