Barrie McKay is reportedly facing two months out of action for Hearts.
The 29-year-old was sent for a scan and consultation with specialists on a knee injury he picked up in the Edinburgh derby win over Hibs.
The playmaker limped from the pitch at full-time after receiving treatment on the knock.
McKay previously face a lengthy spell on the sidelines due to an ankle injury over the summer before suffering a knee issue in the Europa Conference League play-off against PAOK.
Manager Steven Naismith confirmed the latest knee issue is the same knee but "not specifically the same injury" which kept him out for three months.
However, The Scotsman reports McKay could be out for around two months due to the current knee injury.
It's reported McKay faces a minimum of six weeks out of first-team training with the possibility of another week or two on top of that before he could return to action.
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It means McKay faces a race against time to feature in matches against Rangers, Celtic and Hibs in February and March.
Hearts first face Rangers on February 24 which would come just before the possible two-month timeline.
Hibs then visit Tynecastle on February 28 before the Scottish Premiership clash against Celtic on March 3.
It comes as McKay previously admitted it's been a "freak" issue of injuries at Hearts as he stated his otherwise clean bill of health in his football career.
"Since I've come to Hearts I've never been injured," he said. "I've never experienced it before so I have been quite lucky.
"To get two relatively bad ones straight after each other is probably quite freak.
"You need to deal with it, it is the risk you take as a footballer that there is always a chance you can get injured."
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