Hearts captain Christophe Berra is a major doubt for the Edinburgh derby after sustaining a concussion against Motherwell.
The player suffered a head knock during the 2-1 defeat at Fir Park as the Tynecastle side exited the Scottish Cup at the quarter-final stage.
The Scottish international was taken to hospital with the club doctor for further inspection.
With just five days left until Ladbrokes Premiership clash at Easter Road it means the 33-year-old could well miss out.
Berra was instrumental in Hearts’ victory the last time the teams met at Tynecastle Park, putting in the header which led to Don Cowie’s winner, and his absence would be a significant blow for Craig Levein’s side.
Scottish sport guidelines on concussion state that a club should “sit them out” if there’s any doubt over the player’s health.
Berra’s centre-back partner John Souttar missed two games earlier this season after being concussed while on duty with the Scotland under-21 squad.