The 20-year-old headed for scans on Wednesday after leaving the Kangaroos training track early, with club officials unsure of the severity.
But the Kangaroos are fearful he could miss round one, given his hamstring injury history even before he was drafted alongside Sheezel in 2022.
Wardlaw went pick four in the draft, one spot behind Sheezel, cementing a firm friendship.
"I'm shattered for George, I'm not too sure of the extent of it," said Sheezel, also 20.
"We'll see how bad it is but I'm shattered for him and we'll wrap our arms around him.
"He's worked so hard on his body the last few years to get it right so if this is a bit of a setback it will be hard for him.
"He was so fit and firing and ready to go and hopefully he will still be able to show that this year."
North assistant coach Leigh Adam said Wardlaw had completed 90 per cent of the pre-season before the injury blow.
"He's been in some really good form and his body was strong and fit and healthy but unfortunately it looks like he's going to miss a bit of footy," Adams said.
"The one thing I do know about George is that he's really resilient and he's been through it a few times now so he will do his rehab really diligently and make sure he gets himself nice and strong and fit and ready to go but how long that is, we're not too sure."
Despite only heading into his third season, Sheezel was earlier this month voted vice-captain, alongside Nick Larkey, by his teammates.
Jy Simpkin is the sole skipper this season with Luke McDonald stepping down.
"I'm very honoured to be in the role and to be able to support Jy who has done a lot of heavy lifting alongside Luke (McDonald) the last few years and he's more than ready to take the role," Sheezel said.
"I'm excited for the extra responsibility but I will just try and be myself."
George Wardlaw (left) and Harry Sheezel were both drafted by North Melbourne in 2022. (James Ross/AAP PHOTOS)
Sheezel said the squad was "fit and strong" and there was plenty of competition for spots, as well great optimism about the season ahead as they look to climb from second-last spot.
He said the arrival of all-Australian trio, Luke Parker from Sydney, Jack Darling from West Coast and ex-Western Bulldogs defender Caleb Daniel had bolstered their belief.Â
"I want to win some games, climb the ladder and be a part of a successful team, which we haven't been able to do the last couple of years," Sheezel said
"Bringing a few more talented older guys in, and some young kids as well who are showing a lot, I think this is the year so I'm really excited."
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