Apprentice jockey Ross Coakley was taken for precautionary scans on his face following a fall at Ballinrobe on Monday.
The incident happened after his mount Grandma Dotty slipped up in the Tote Apprentice Handicap.
As a knock on effect of the fall Donagh O'Connor was brought down aboard the Garvan Donnelly-trained Mallory Heights.
Although O'Connor walked away unscathed Coakley was taken to University Hospital Galway for further treatment.
Dr Adrian McGoldrick, chief medical officer for the Turf Club, said: "Ross lost consciousness for about 30 seconds but came around very quickly and was quite alert.
"He had some swelling around his right eye and is having a precautionary CT scan on his facial bones. There is no other injury at this stage apart from the concussion.
"Things seem to be more positive than were first thought which is good.
"Donagh walked away from the incident fine."