Philippe Clement has admitted there is "no guarantee" that Robin Propper will be first for this weekend.
The Rangers boss revealed the centre-back was not involved in training on Friday ahead of the Scottish Cup tie against Fraserburgh.
However, there is a strong chance Propper will be back tomorrow, dependent on medical results.
The defender was forced off in the 3-0 win over Aberdeen due to an injury issue with Leon Balogun making his return to the Rangers first-team having been sidelined himself in recent weeks.
"Robin still felt something today," said the Rangers manager of the fitness of the former FC Twente captain.
"But there is a big chance he will be in the training tomorrow.
"No guarantee yet for medical stuff. But the chance is big."
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Philippe Clement provides Jack Butland Rangers injury update
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Rangers will be without Danilo and Oscar Cortes for the match on Sunday with question marks over Jack Butland's availability.
"Danilo will be out, not a full assessment yet about that case, and Cortes also," said Clement.
"The other players who were not available before will not be available.
"Jack Butland is still a question mark, but he's also close to coming back into training with the squad.
"We will see tomorrow if he can play with the squad and what conclusions to make about that."
