Kevin Thomson's season is almost certainly over after scans revealed major damage to the Rangers midfielder's left knee.
Thomson will undergo more tests but the initial diagnosis is that he could be out for up to eight months after damaging his knee in the 4-0 win at Kilmarnock.
Rangers revealed Thomson will see a specialist in London but the Ibrox medical staff fear the worst following hospital tests on Monday morning.
It is feared Wednesday's appointment will confirm Thomson faces another fight to overcome cruciate ligament damage.
The 24-year-old's knee buckled under the weight of David Fernandez as he tackled the Kilmarnock striker towards the end of Sunday's Clydesdale Bank Premier League clash at Rugby Park.
He suffered a cruciate ligament injury as a teenager while playing for Hibernian in May 2004, and was out of first-team action for 11 months.
Thomson, who made his Scotland debut against Northern Ireland in August, has recently produced his best football since his £2million move from Easter Road in January 2007.
Rangers legend Mark Hateley believes the loss of Thomson, who scored a spectacular late equaliser against Dundee United last week, is a "huge blow".
"Since Kevin came to the club we've seen an improvement in the overall play of Rangers," Hateley said.
"When he was out last season, it was clear how much they missed him. I think he has been inspirational this season. His link up and his immediate success with Pedro Mendes has been miraculous."
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