Rangers have revealed that Steven Whittaker has undergone a hernia operation and will be sidelined for up to six weeks.
The full-back travelled to England to visit a specialist on Tuesday after struggling with a niggling knock for some time.
It was determined that surgery was the best way forward and he was sent under the knife almost immediately.
Whittaker is expected to be missing until the end of February, ruling him out of important league and cup fixtures.
A statement released on Rangers' official website read: "Whittaker will be absent for SPL meetings with St Johnstone, Aberdeen, Hibernian, Dunfermline, Kilmarnock and probably Inverness as well.
"Likewise, he'll miss the home William Hill Scottish Cup clash with Dundee United at Ibrox on Saturday, February 5.
"Whittaker could be fit in time for Scotland's away friendly with Slovenia on February 29 but the chances are he won't be risked.
"That means a realistic comeback date could be March 3, when the Light Blues entertain Hearts at Ibrox."
Rangers have also announced that Whittaker's replacement at full-back, Kirk Broadfoot, is to have a scan on the knee problem that he has been nursing.