Scotland hooker Dougie Hall will miss this Autumn's Rugby World Cup after sustaining an injury in training.
Hall, 26, tore the medial ligament in his left knee and suffered some additional minor damage to the joint, during a squad session on Monday.
Scotland team doctor James Robson said: â€œFollowing the injury at training, we arranged for Dougie to go for a scan, the results of which we received last night. The scan confirmed our initial diagnosis that he has torn his medial ligament and sustained some additional minor damage to the joint.
"We will now embark on further assessment and treatment but the average recovery time for this type of injury is 12-16 weeks."
Scotland head coach Frank Hadden said: "It's obviously disappointing news for Dougie and I wish him a speedy recovery. He has made enormous progress in the last couple of years and been integral to the national squad in that time."
Hall won the first of his 19 caps four years ago and although he was part of Scotland's squad at the 2003 Rugby World Cup in Australia, he did not feature in a match 22 on that occasion.
Hadden has added Hall's Glasgow Warriors team-mate, the uncapped 23-year-old Fergus Thomson, to the Scotland squad.
Hooker. Born: 18.10.1983 in Dundee. Height: 6ft (1.83m). Weight: 16st 4lb (104kg).
Fergus Matthew Andrew Thomson experienced Heineken Cup rugby with Glasgow Warriors as a 19-year-old when he appeared as a replacement in the match against Sale Sharks at Heywood Road in January 2003, though it was nearly two years later before he made his Celtic League debut as a substitute in the Hughenden victory against The Borders in November 2004.
His first start for Glasgow was not until three years after his debut, and that, too, was in a Heineken Cup tie, when Warriors beat Bourgoin at Firhill in January 2006. By then, he had played 20 Glasgow games as a replacement. Fergus appeared in all three of Scotland A's matches in the Barclays Churchill Cup in Canada in June 2006 and again in the A international win against Italy at McDiarmid Park, Perth, in February 2007 as well as the three Churchill Cup games in England later this year. He had earlier worn the Scotland colours in under-19 and under-21 international rugby.
His under-19 honours included the IRB's 2002 World Junior Championship, and in the two subsequent years he played in all but one of Scotland's 21 under-21 internationals, with a run of 16 in a row that included a 33-22 win against England at Newbury in the 2003 IRB Under 21 World Championship. Fergus is a member of the Scottish Institute of Sport. His father, Mel, is a former British Universities' weight-lifting and boxing champion and his brother, Graham, was a member of the Scotland Club International side that beat their Irish counterparts this year.
Scotland u19, u21 and Scotland A.