The AlphaTauri driver suffered a metacarpal fracture in practice for last month's Dutch Grand Prix, ruling him out of the Italian Grand Prix one week later as the Australian underwent surgery in Barcelona.
Horner, whose team has loaned out third driver Ricciardo to sister squad AlphaTauri, says Ricciardo's recovery is going to plan but he believes the next double header on the calendar in Singapore and Japan is going to come too soon for the 34-year-old.
