Phil Hughes has been hospitalised after receiving a blow to the head while batting for the West End Redbacks in their Sheffield Shield match against the New South Wales Blues.
The incident occurred when the 25-year-old attempted to hook a delivery from Sean Abbott, but the ball struck him directly on the head.
Hughes stood up with his hands on his knees following the blow, but then collapsed to the turf and lay motionless before medical staff rushed out to treat him on the pitch.
The batsman was then treated off the field by doctors where he received mouth-to-mouth resuscitation before he was taken to hospital in an ambulance, where reports suggest that he is in a critical condition.
New South Wales said on Twitter: "Phil Hughes has been taken to a nearby hospital via ambulance. A full statement on his condition will be made once assessed by doctors."
Play was immediately abandoned for the day at the Sydney Cricket Ground following the incident.