Scotland trio Tommy Seymour, Blair Kinghorn and Stuart Hogg have been ruled out of Saturday's Guinness Six Nations clash against England at Twickenham.
Wing Seymour (rib) and utility back Kinghorn (ankle) both sustained injuries in Saturday's defeat to Wales and join full-back Hogg on the sidelines.
Hogg damaged his shoulder in last month's home defeat to Ireland and missed the 18-11 loss to Wales at Murrayfield.
"Consequently, head coach Gregor Townsend has added Glasgow Warriors pair Ruaridh Jackson and uncapped Kyle Steyn to the squad," Scottish Rugby said.
Scottish Rugby also confirmed Warriors duo Adam Ashe and Tim Swinson, plus Edinburgh pair James Johnstone and Luke Crosbie, had been released back to their clubs.
Scotland will defend the Calcutta Cup against England at Twickenham in their final match of the tournament having won the corresponding fixture last year at Murrayfield 25-13.
Townsend's side beat Italy in their opening 2019 Six Nations match, but have since lost to Ireland, France and Wales and are fourth in the table.
