The 33-year-old, who has been battling a right calf strain during the pre-season, told FoxSports on Wednesday night he is unlikely to be fit in time for the opening round of the season.
However, the veteran is confident of returning in round two against West Coast.
“I’m not far away at all but I think conditioning-wise, I’m going to end up a session or two short,” Montagna said.
“So most likely, I’ll miss round one and definitely be available for round two.
“This time of year the last thing you want to do is re-injure it, so we’re not going to rush it.”
Montagna played every game last season, averaging 26.7 disposals, 6.1 marks and 2.7 tackles.