Kimi Raikkonen has so far outperformed his teammate in the 2016 Formula One Championship. Scuderia Ferrari expected that Sebastian Vettel would be their top driver in 2016, however, Raikkonen has more points and podium to his record.
Based on Kimi Raikkonen's current form and pace, there seems no need to replace him. Maurizio Arrivabene, Team Principal admits that Scuderia Ferrari is keen to retain Raikkonen if he wishes to race in Formula One. Kimi Raikkonen's contract with Ferrari ends with the 2016 Championship.
Currently, Kimi Raikkonen is the oldest driver in the Formula One paddock at the age of 38. Age will definitely not play a factor in choosing their driver line-up, only performance matters to Ferrari. Raikkonen has improved his pace and form over last year, which works in his favour.
Scuderia Ferrari wants Kimi Raikkonen to maintain his current form. Only if the Finnish driver can perform consistently throughout the season will the Italian team retain him. There is a possibility that one of their younger development drivers could take Kimi's place.
Sebastian Vettel has witnessed some terrible luck during the 2016 F1 Championship. Ferrari is confident that he is a good racer and will eventually get back into his rhythm. Both Raikkonen and Vettel are Champions and are important for Ferrari's title contention.