Only the docs will know for sure how bad this is, but, based on the estimated time out, it would appear bad. I do hope this is not career ending for him. A chance for Umaga to step up though. I know Miller will be covering 10 for now, even though Umaga is back with us. What will Dai do? 10 is a key position to know you can't fill for that long.
It really is a massive pity this has happened, he was starting to grow into the role when he stepped up. I guess Umaga is now recalled as additional cover for 10 and also 15.