The former Internacional star is one step closer to a comeback after joining his team-mates for a full session on Thursday morning
The 23-year-old has yet to make an official appearance for the Rossoneri this term due to an adductor problem, and had spent the past few weeks working on his recovery.
However, he is now one step closer to a comeback after participating in a full group training session on Thursday, without any reaction to his original injury.
It remains to be seen whether Pato will make the squad for the Derby della Madonnina, though, with Milan keen to ease him back into action and avoid any further long-term problems.
Sunday's match versus Inter is scheduled to kick off at 20:45CET.