Borna Barisic has handed Rangers an injury scare just seven days before the crucial Premiership clash with Celtic.
The left back limped out of Croatia's Euro 2020 qualifier with Hungary after just 29 minutes on Sunday.
Reports suggest the 26-year-old has picked up a muscle injury in his leg.
Barisic has been close to finding his best form in recent weeks and scored for Croatia in the 2-1 win over Azerbaijan on Thursday.
But Steven Gerrard could be forced to rethink at left back if the summer signing is indeed struggling.
Andy Halliday has filled in on the left of defence and would be first option ahead of Jon Flanagan who has been out of the picture since January.
Rangers need to win at Celtic Park next Sunday if they are to keep their slim title hopes alive.
The Ibrox club sit 10 points behind the leaders with eight games remaining.
