 Complete the following phrase:  The 2012 season saw several driver changes. Lotus chose not to take up an option on Vitaly Petrovs contract, and did not offer Bruno Senna a new contract. Petrov and Senna were replaced by World Drivers Champion Kimi Räikkönen  returning to the sport after two seasons competing in the World Rally Championship  and reigning GP2 Series champion Romain Grosjean, who also returned to the sport after a two-year absence. Petrov later replaced Jarno Trulli at Caterham; Trullis replacement meant that the opening race of the season would be the first race since the 