Reid won't require surgery and will instead undergo a rehabilitation and strength program over the next four weeks after being diagnosed with a grade three strain of his right shoulder.
Scans revealed he didn't suffer a dislocation.
Reid contacted the club reporting soreness in his shoulder after an innocuous incident on a Thai beach over the new year period.
He returned to Melbourne on Wednesday and was assessed by club doctors. He hopes to be available for selection at some stage during the club's pre-season campaign.
Reid, 22, has played 51 games for Collingwood after being selected by the Magpies with the eighth overall pick in the 2006 draft. He was a member of the 2010 premiership side and was named at centre-half back in the 2011 All Australian team.
Collingwood players return to training next week following their Christmas/New Year break.
