Hirvonen spoke about Raikkonen's competitive return to F1 last year.
Jan.11 (GMM) Mikko Hirvonen, the 2012 world rally championship runner up, believes countryman Kimi Raikkonen would have kept improving had he stayed in rallying.
McLaren and Ferrari, finished the 2012 season in third place as he made his return to the sport.
In 2010 and 2011, following his split with Ferrari to make way for Fernando Alonso, the now 33-year-old opted to try his hand at world rallying.
Speaking about Raikkonen's competitive return to F1 last year with Lotus after two seasons away, Hirvonen said: "Well, it was not really a surprise.
"This man knows how to drive F1 (cars). When I heard he was going back, I thought that if the car is good, he will survive -- and Kimi did very well," he told Turun Sanomat newspaper.
But Hirvonen thinks Raikkonen would have kept improving had he stayed in rallying.
"The results would certainly have improved, but how much would have depended on how much enthusiasm Kimi had for practicing and testing.
"But his pace would definitely have improved in the third season," he added.