Edinburgh back-row forward David Denton will play no part in Scotland's summer tour because of injury.
The 24-year-old had been expected to feature in Friday's Test against Argentina, and against South Africa in Port Elizabeth on 28 June.
But he is not fully fit after being concussed in Edinburgh's final game of the season against Leinster last month.
The Scotland management will now consider additional options for the South African leg of the tour.
"David has not recovered sufficiently for the intensity of Test rugby," said Scotland doctor James Robson.