The Portuguese giants could be without up to eight first-team stars for the Ibrox clash.
Adel Taarabt is the latest Benfica player to test positive for Covid-19, joining Julian Weigl and Darwin Nunez in self-isolating.
Taarabt and Weigl started the meeting between the two sides in Lisbon which ended 3-3, while Nunez came off the bench to net the stoppage time equaliser.
David Tavares and goalkeeper Mile Svilar have recovered after testing positive but Tavares has picked up an injury, joining a list which includes Nuno Taveres, Andre Almeida, Jean-Clair Todibo and Pedrinho.
Benfica, who sit third in Liga Nos, haven’t played since November 8, a 3-2 defeat to Braga.
Rangers are top of the Europa League difference ahead of their opponents on goal difference. A win at Ibrox would be a huge step towards qualification to the group stage.