Gio van Bronckhorst is hoping to find out on Friday how long Alfredo Morelos will be out for - with Sunday's derby with Celtic looking increasingly doubtful for the Colombian.
The firing striker was seen on crutches after international duty and flew to London on Thursday to see a specialist.
And it now appears Rangers need a miraculous comeback if he is to be fit to face Celtic at Ibrox this weekend.
Gers boss Van Bronckhorst hopes he won't be out long-term.
Rangers are waiting for the results of the medical assessment before they get a full extent of Morelos ’ injury.
The Light Blues are looking to claw back Celtic’s three point lead in the Premiership and are also gunning for glory in the Scottish Cup and in the Europa League, where they face SC Braga in the quarter-finals.
Morelos’s 19 goals have played a big part in their success up to this point.
The influential striker had to drop out of the Columbian squad early with a muscle issue, missing out the win over Bolivia and then Wednesday’s triumph in Venezuela.
A Colombian statement, earlier this week, confirmed: “The technical and medical staff of the Colombia men's senior national team reports that, after performing medical tests on player Alfredo Morelos, a muscle injury in the left thigh was confirmed, which prevented him from participating in the previous match against Bolivia and likewise does not allow him to participate in the next match of the qualifiers for the FIFA World Cup Qatar 2022.”