Ibrox wide-man Chris Burke could also be out for six months after his ankle surgery.

Both players were injured in the Scottish Cup semi-final against St Johnstone at Hampden Park on April 20.

Burke, 24, was substituted seven minutes in after being caught by Kevin Rutkiewicz while 22-year-old Naismith's season ended when he fell victim to a Martin Hardie tackle which led to cruciate ligament damage.

Burke and Naismith underwent successful surgery yesterday but the estimated length of their respective lay-offs will shock Ibrox boss Walter Smith, who is preparing his side for the last Clydesdale Bank Premier League clash of the season against Aberdeen at Pittodrie on Thursday night.

Goalkeeper Allan McGregor continues his recovery from an ankle problem sustained against Celtic last month.