Ulster have confirmed that Ireland captain Rory Best faces up to six weeks on the sidelines with a hamstring injury.

The 35-year-old, who captained the British and Irish Lions' midweek team during this year's tour of New Zealand, initially sustained the problem in training with Ulster last week and the Pro 14 side have now confirmed he faces a sustained period on the treatment table.

"Following a scan, it has been confirmed that Rory Best has a hamstring tear and will be out of action for approximately four to six weeks," Ulster said in a statement."

Best's injury will come as a huge blow to Ulster, who are due to get their Champions Cup campaign under way against Wasps in Belfast on October 13, while the hooker is also expected to miss the trip to French club La Rochelle nine days later.

The experienced forward, who has won 114 caps during a 12-year international career with Ireland, is likely to be fit for his country's autumn internationals, which begin with a match against South Africa at the Aviva Stadium on November 11.