Iwelumo suffered the injury in a pre-season friendly against Perth Glory earlier this month and looks set to be sidelined until around October.
But he is maintaining a positive attitude following a successful operation and is now looking forward to stepping up his rehabilitation.
"The operation went well and I'm now just getting ready for rehab," he told the club's official website.
"It's just a case of making sure there's no reaction but then once I'm off the crutches I'll be straight into it.
"They're saying it's about three months so we'll just get on with it and see how it goes.
"Maybe it's a slight consolation that by the time the season starts I'll be a good few weeks into the recovery but obviously I was hoping to be involved.
"It's just a case of trying to get myself back and fit and trying to make an impact when I am."
Iwelumo is confident that his team-mates will acquit themselves in the Premier League after winning promotion at the end of last term.
He said: "We have made some great signings of not only good players but also good lads who have really settled in well with the rest of the squad.
"Everyone is already looking fitter than we were last year which was already a pretty high standard to reach, and hopefully we can pick up where we left off last season."