Ferrari justified the move on the basis that Massa couldn't support teammate Fernando Alonso's title-charging points hauls on a regular enough basis, but the 32-year-old thinks Raikkonen will also struggle alongside the Spaniard.
Having tipped Alonso to beat Raikkonen while talking to the Italian press at Jerez, Massa explained: "Because he's very intelligent and has already grasped the new rules.
"He (Alonso) knows what he needs to do to be fast from the beginning," he is quoted by Speed Week. "He combines talent with brains.
"He really is clever, and that is what you need for rule changes as drastic as these," added Massa.
However, Massa said Raikkonen cannot be completely ruled out.
"Maybe the new Ferrari will be better suited to Kimi's driving style," he admitted. "We'll find out."
There have also been doubts about whether Alonso, formerly the clear number 1 alongside Massa, will be able to work harmoniously alongside Raikkonen, the last Ferrari champion.
But team boss Stefano Domenicali said he was "very pleased to see" how harmoniously the pair had worked together at the Jerez test last week.
Alonso also revealed that he spent some days at Maranello with Ferrari's returnee recently.
"We had some fun evenings," he is quoted by Italy's La Gazzetta dello Sport.
"There will be a total sharing of data between us, which is what we are used to at Ferrari," Alonso insisted.
"Every day I had every lap of telemetry from Kimi, and he will also have mine. And what I'm trying here at Jerez, he will try in Bahrain," he added last week.