An operation to a shoulder problem in the summer requires three months rehabilitation, putting Ferg out of action until at least October.
"I had to get the capsule in my shoulder tightened up and I tore my rotator cuff and bicep tendon," Ferg told The Scotsman. "It was more a wear-and-tear injury, and it was always there last season affecting me to some degree. I went through phases where it was no problem and others where it was quite troublesome.
"I knew I had to get an operation when it got to that stage, but I don't think the seriousness of it was diagnosed immediately. Once it was, then I was in (for the op] and I'm just glad to have got it done now and be looking forward. I would definitely like to have been ready for the start of the season, but that's not the case.
"It is frustrating and will probably be more so when the season actually starts, but the one thing this has done is given me a good off-season.
"With the Churchill Cup and U-21s commitments, I've only had one proper off-season in the last six years, so hopefully with a good break I'll be fresher than ever and be playing my best rugby when I come back."