Leicester and England fly-half Toby Flood was taken to hospital after suffering a blow to his head during a pre-season game with Ulster on Saturday.
The Tigers skipper left the pitch at Welford Road on a stretcher with an oxygen mask strapped to his face after being struck in the face by Ulster lock Dan Tuohy's arm in a tackle. Tuohy was sent to the sin-bin as a result.
The 28-year-old Flood is reported to have left the ground in an ambulance after lying motionless on the ground during a 12-minute stoppage following the incident which happened just 10 minutes into the game.
The injury will come as a major scare for Leicester and Flood, who was also forced off the field after being knocked unconscious in his last competitive appearance - the Premiership final last May.