SCOTLAND'S back row resources have been rocked by the news that Ross Rennie is to retire from rugby, aged only 28.

After a career undermined by injuries he has accepted that his latest setback, a neck problem, means he cannot go on playing.

As recently as last November, Vern Cotter, the Scotland head coach, said he was keeping tabs on the player, who won 20 caps between 2008 and 2012 and could have been the answer to his openside flanker issues had he ever regained full fitness.

Perhaps, given Rennie's medical history, it was no surprise that he didn't, but Andy Robinson, the coach who gambled on using Rennie in the Rugby World Cup squad in 2011 and who later created a spot for him to relaunch his career at Bristol, was in no doubt what Scotland have lost.

"I've worked with Ross from a young age, and at his peak he was one of the best openside flankers in the Northern Hemisphere - a world-class performer," Robinson said. "Unfortunately, injuries have hampered Ross's progress, but his attitude and willingness to learn has not been dampened. He can leave the sport proud of his international achievements and with some great memories."

Rennie himself was philosophic about his latest misfortune: "I feel very fortunate that the sport has given me the opportunity to travel the world, meet new people and represent my country - something that I'm immensely proud of," he said. "Obviously, it's disappointing to stop playing the game that I love, but the support I've received from Bristol has been brilliant."

His career has always been blighted by injury. After making is Test debut in 2008, he missed the rest of that year with a knee injury, which he then aggravated on his return to action, ruling him out of rugby until the start of 2010. He did make the 2011 World Cup squad, and overtook John Barclay to be first choice in 2012, only to dislocate his shoulder in the final Test of the year and again aggravate the injury on his return the following spring. His knees have again been troubling him over the last year but it is a neural problem in the neck that has finally forced him to quit.