Jockey Jordan Gainford was taken to Aintree Hospital following a fall from Minella Sixo at Haydock.
The Gordon Elliott-trained six-year-old was just getting into contention in the opening Pertemps Network Handicap Hurdle when he suffered a heavy fall at the third-last flight.
Gainford – who has enjoyed a terrific association with Hewick in recent seasons, with victories including the bet365 Gold Cup at Sandown and the Galway Plate – was quickly attended to by the medical services and was reported to be conscious before he was transferred for further assessment.
A Jockey Club spokesperson said: “Jordan has been taken to Aintree hospital for further assessment. He was conscious.”
There was a 25-minute delay to proceedings while medical teams got back into place.