Troubled with knee pain after the 2010 season and on the pre-season camp in Utah, Lower went in for surgery shortly after returning home.
North Melbourne chief of football Donald McDonald told kangaroos.com.au Lower’s recovery was expected to take some time.
“It’s been a long process for Ed but we were acutely aware of that when he had his surgery.
“Ed has been meticulous in his rehabilitation up until this point but unfortunately, he hasn’t been able to overcome the injury.”
Lower has remained upbeat throughout his recovery period and recently told the Adelaide Advertiser's Rebekah Devlin he has a renewed hunger to make it back onto the field this year.
"I'm a pretty realistic person. I know it's do or die I guess for me," he said.
"It's pretty frustrating at times...but it's something you have to deal with, and I'm trying my best to do that.
"The funny thing is the longer you're out, the more excited you get about your footy, so I'm more excited than ever seeing I've been out for a while now."
