"It's been two months since the operation," he told the Evening Post.
"I'm now building up the muscles around the knee and at the moment things feel good, there's no swelling or irritation.
"The surgeon took a graft from my hamstring to repair the knee ligament, so that means my hamstring is a little bit weak for the time being.
"That has to heal properly, which takes a couple of months, then I'll really be able to step up my work.
"I'm training twice a day, in the gym in the morning then running and exercising in the water in the afternoon.
"At first I could only do very light weights in the gym, but I'm moved on to some heavier ones now, which is good.
"I hope to be back training with the first-team squad at some point in October.
"If I was playing club football in Sweden, perhaps I would probably need two weeks' training before playing, but this is the Premier League.
"It's tough enough to play there in the first place, let alone after six months out injured, because it's so high-tempo."