Harlequins director of rugby Conor O'Shea was left counting the cost of Sunday's Heineken Cup defeat at Clermont Auvergne after discovering hooker Rob Buchanan is set to be sidelined for three months.

The 22-year-old was forced out of the 23-16 reverse early in the first half with a shoulder problem and scans at the weekend confirmed he will require surgery this week to repair torn muscles.

Quins, who lost back row Maurie Fa'asavalu to a hamstring problem in last week's defeat to the Scarlets, have a lengthy injury list and, with England Saxons hooker Joe Gray still recovering from an ankle problem, now have a crisis in the front row.

Former Cornish Pirates man Dave Ward, who impressed as Buchanan's replacement at the weekend, is the only senior number two fit for action with 21-year-old academy youngster Harry Allen - who has one LV= Cup appearance to his name - his back up.