Young midfielder Brown suffered a serious knee injury while playing for Forfar in the 3-1 defeat to Cowdenbeath.
Scans have revealed that he's sustained damage to his cruciate ligament following a tackle from behind after just two minutes.
Loanees Brown, Nicky Low and Joe Shaughnessy have all impressed while on loan at the Second Division side.
Everyone at Aberdeen Mad wishes Jordon a full and speedy recovery.