Giovanni van Bronckhorst has confirmed that Alfredo Morelos will miss the Old Firm on Sunday.
The 25-year-old striker sustained an injury whilst on international duty with Colombia.
Morelos returned early but he was pictured travelling to London to visit a specialist on Thursday afternoon.
Rangers welcome Celtic to Ibrox on Sunday afternoon with Ange Postecgolou's side holding a three-point lead at the top of the Premiership table.
Gers boss van Bronckhorst confirmed that Morelos is injured and he's likely to be out longer term.
He told Sky Sports: "Alfredo unfortunately had a new injury while on duty with Colombia so he wont be available for this Sunday.
"We will lose him for a longer time. We will assess him for next few days. He's out for Sunday.
"It's always a blow when you lose players, not being able to play in games.
"Morelos is an important player for us. We have a big challenge ahead of us in the coming weeks, months.
"We have to be ready and make sure the ones who are able to play are well prepared."
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