The leading candidate to replace Raikkonen at Lotus is the German Nico Hulkenberg.
Massa, admitted he needs to put his focus on the road in front of him.
According Force India's sporting director Otmar Szafnauer, Pirelli's mid-season tyre specification switch badly hurt some teams like Force India.
According to Blick newspaper, Hulkenberg and his manager Werner Heinz are having "sleepless nights".
Nico Hulkenberg may end up with Force India in 2014.
According to sources inside the Lotus team, Finn Kovalainen will shortly be announced by Lotus as Raikkonen's replacement for the last two Grands Prix of 2013.