Aidan Coleman will be declared to ride Coneygree in the Betfair Chase at Haydock on Saturday - but Richard Johnson could still end up taking the mount if Menorah is a non-runner
With regular rider Nico de Boinville on the sidelines, champion jockey Johnson had been first choice to partner the 2015 Gold Cup winner on his much-anticipated return to action.
However, Johnson has been claimed by his boss Philip Hobbs to ride Menorah in the same race.
But with plenty of rain forecast, connections may decide the ground is unsuitable and withdraw him from the Grade One on Merseyside.
Should that be the case, Coleman has been informed by Coneygree's team that Johnson will take over aboard the nine-year-old.
Sara Bradstock, assistant trainer to her husband, Mark, said: "Basically, Aidan Coleman will be declared to ride Coneygree.
"We're of the understanding Richard is riding Menorah but if for any reason Menorah doesn't run then Richard will step in.
"Aidan is fully aware of the situation and is fine with it."
The British Horseracing Authority said on Thursday morning that the Bradstocks would be allowed to make the proposed change under the rules of racing.