The latest blow comes after a year after Wells' 2012 campaign was threatened after he suffered blood clots in both lungs following routine shoulder surgery.
North Melbourne has set the 27-year-old on a restricted program in a bid to have him fit for round one.
“He was never going to join in full training until after Christmas and we’re graduating his program through and we anticipate he’ll be fine to go for the start of the year,” Kangaroos coach Brad Scott told nmfc.com.au following the club's first training run since the Christmas break on Monday.
“He’s got a really good fitness base behind him but we won’t take any risks with him.”
Wells has a long history of restricted pre-seasons, with the club reporting his only unhindered run came before the 2011 season, in which Wells won All Australian selection and the club's best and fairest.
Wells came back strongly after his blood clot health scare, managing to play 20 games, averaging 22 possessions a game and finishing seventh in the club's best and fairest.
But Scott said Wells' age and aerobic capacity would help him get through this latest setback.
"Wellsy, we think, has got a really good training base behind him so we know what a class act he is, we just need to get him fully fit and feeling his best because to do the things he’s capable of doing, he’s got to be fully fit without any injury worries so we’re confident he’ll be right for round one,” Scott said.
“It’s a little bit unlucky for him but last year even though he had the blood clots issue, he still got a lot of aerobic work in and the year before he had a terrific pre-season so we know what he’s capable of when he’s fully fit, so our focus is on just getting him fully fit and not taking any risks.”
