"Investigations are still going on and it all depends on talks with the doctors and the ambulance staff on the day," the Jockey Club director of public affairs, David Pipe, said.
"We have got to work out how long he was unconscious. I wouldn't think there will be any more news today."
The Gold Cup and Champion Hurdle-winning rider had been expected to return to the saddle this Saturday, having been stood down for 10 days following a fall at Uttoxeter last Tuesday.
But his spell on the sidelines could be extended to three weeks, ruling him out of Aintree, due to reports that he was unconscious for almost three minutes. Jockey Club rules state that a jockey should be suspended for a minimum of seven days if he suffers a short period of unconsciousness.
If McCoy was found to have been knocked out for more than a minute the enforced absence is 21 days.
Brett Doyle is near to a second successive United Arab Emirates jockeys' championship following a treble at Abu Dhabi on Sunday.Reuse content