It is believed that Räikkönen has opted to have surgery now so that his preparations for 2014 are not impacted.
Lotus F1 Team will make an announcement about Räikkönen's replacement in due course. One possibility is for the team to promote third driver Davide Valsecchi. The 26-year-old Italian won last year's GP2 Series, although he has no prior F1 race experience.
Another option is to hand reserve driver Jerome d'Ambrosio the drive. The 27-year-old Belgian has 20 Grand Prix starts to his name and was drafted into Romain Grosjean's car for last year's Italian Grand Prix after the Frenchman was handed a one-race ban.