JP McManus' retained rider only recently returned to action after recovering from a punctured lung and broken ribs sustained in a fall at Kempton in February which ruled him out of the Cheltenham Festival.
His fortunes appeared to have taken a turn for the better when he rode a Grade One treble at Aintree on Defi Du Seuil, Buveur D'Air and Yanworth, but misfortune has struck again.
Riding Minella Foru for Eddie Harty in the Easter Monday feature, he fell at the eighth fence, bringing down Arbre De Vie in the process.
It was soon confirmed Geraghty had broken his left arm, having broken his right arm in a fall at Market Rasen last July.
The rider told At the Races: “I've broken my left humerus and will have it plated today. I'd expect to be off for 10 to 12 weeks.”