Scotland number eight Simon Taylor has suffered a serious knee injury that will force him to miss the summer tour to South Africa.
The 26-year-old, whose career has been blighted by injury, has been told he will be out of action for at least four months after a scan revealed significant damage to his knee.
Taylor, who has been selected for the last two British & Irish Lions tours only to be forced home early because of injuries, suffered his latest setback playing for Edinburgh in Friday's 22-16 Celtic League win over Connacht.
He will undergo surgery on his medial ligament next week, although the scan and subsequent examination showed no significant injury to his previously reconstructed cruciate ligament.
Taylor will begin rehabilitation with the Gunners' medical staff.