The 2011 All-Australian is yet to resume full training and coach Nathan Buckley admits Thomas has a lot of work ahead of him to push for a spot in the round-one team to play North Melbourne on March 31.
"It's still a couple of months away," Buckley said on Friday when asked about Thomas' Round 1 prospects.
"He'll need to get some solid training in and get up to speed before he's ready to play games of footy.
"Whether that's late in the (pre-season cup) or early in the home-and-away season will depend on the speed of his recovery.
"He's had a modified pre-season. He's got a lot of fitness work in but not on legs.
"Clearly, he's an important player for us."
The Magpies are hoping the 25-year-old wingman's out-of-contract status doesn't become a running story this season in a similar fashion to key forward Travis Cloke's saga in 2012. Cloke eventually re-signed with the Magpies.
"We've got about 40 per cent of our list coming out of contract this year and we'll deal with those guys, appropriately, at the right times," Buckley said.