Gloucester will head into their make-or-break Heineken Cup matches against Cardiff Blues and Biarritz in the new year without Greg Somerville after he suffered a detached retina in his left eye.

The New Zealand prop, who has played just 110 minutes of rugby for Gloucester, was injured during the 42-12 Guinness Premiership drubbing at London Irish five days ago and has had surgery to reattach the retina in his left eye.

The tighthead, a big-money recruit from Canterbury Crusaders last month, will also definitely miss the Premiership matches against Bristol, Saracens, Newcastle, London Irish, Sale and Harlequins.

He is not expected to be seen on a rugby field again before late February, potentially leaving Gloucester short of cover at tighthead during the Six Nations Championship period.

Head coach Dean Ryan, whose side face Bristol at the Memorial Stadium on Saturday, said: "First and foremost, this is a huge blow for Greg. We really hope everything has gone well, because his health is the most important thing.

"Secondly, for him to be new at a club and immediately get injured is very sad. Every player that moves around is potentially exposed to that sort of risk, it's just sad when it happens. It leaves you a little bit on the outside and it's difficult to integrate while you are on the sidelines.

"And thirdly, the whole idea of having a man of his stature and experience was to help us and we are clearly going to miss that influence over the coming months."

The 31-year-old, a 66-time All Black, was operated on by consultant ophthalmologist Mr Rob Johnson at Cheltenham General Hospital.

And while Ryan expects Somerville to become a major off-field influence during his spell out of action, he is also understandably cautious about rushing his new recruit.

"I think he can still have an influence – and we will get him involved in a lot of stuff as soon as he's up," said Ryan.

"But the first couple of weeks – with an injury of that type – will be pretty low-key and his health is the most important issue. Let's get that right, and then we will look to get him involved behind the scenes."

The timing for both Somerville and Gloucester is disastrous, with the prop having been desperate to make an instant impact at Kingsholm.

"It's unbelievably bad luck, not only for Greg but for the squad, because everyone was looking forward to working with him at this crucial stage of the season," added Ryan.

"Our thoughts are with Greg, because this is a nasty injury and will take some considerable recovery time.

"We will obviously miss his contribution as a world-class player and we wish him well for a speedy recovery."

While Somerville joins Gloucester's long-term injury list, Ryan's short-term problems also show no sign of easing. He will head to Bristol on Saturday without flankers Peter Buxton (ankle) and Andy Hazell (knee), as well as centre Anthony Allen (ankle). But full-back Iain Balshaw is back in contention after a groin problem.