The 25-year-old collapsed after being struck on the side of the head by a Sean Abbott delivery and was stretchered from the ground. He is currently undergoing surgery and according to Ambulance officials he was in a critical condition.
A statement issued by South Australia Cricket Association said: "On behalf of the SACA Board and administration, our thoughts and prayers are with Phil Hughes and his family at this time.
The South Australia Cricket Association CEO, Keith Bradshaw, spoke briefly to the media, saying he's "very shocked" and "very upset" by the incident.
He said the outcome of Hughes' surgery is unlikely to be known for 24-48 hours.
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Cricket Australia CEO, James Sutherland also spoke to reporters.
"To be honest it sends shudders through you a little bit," he said.
"Pleasingly there was medical attention he was able to receive immediately at the ground.
Hughes was given CPR on the stretcher as he came off the field, with Australian opener David Warner alongside him.
At least three ambulances and a helicopter were on hand to treat the 25-year-old and transport him to St Vincent's Hospital.
Australian captain Michael Clarke was one of the first people to rush to the hospital and is currently with Hughes's sister and mother Virginia who were at the SCG today.