Massa said there were parallels with his own situation in his final years at Ferrari, saying that even the 'Iceman' is not impervious to the weight of scrutiny and expectation of driving for the Scuderia.
"One of the problems that Kimi has is [mental]," Massa said. "It is not easy to be in that position, and definitely he is suffering more with the pressure than other things. Everybody says he is the ‘Iceman’, but he is not really like that; for sure he can suffer as well with the pressure, and he shows (that) with (his) results.”
Raikkonen has scored just one podium finish this season. By contrast, team mate Sebastian Vettel has secured five, including a win at the second round in Malaysia.
"He is definitely a big talent and he can do a lot better than what he is doing, everybody knows that,” continued Massa. “It is related to him. I'm sure I felt a lot of pressure (at Ferrari) in difficult moments. He just needs to relax and try to do his best."
Massa, who spent eight years racing for Ferrari - including three with Raikkonen as his team mate, said that while Maranello is a nurturing environment, the fact that other drivers are often linked with the squad can be very unsettling.
"I think the team supports you definitely," he added. "But it is not just the team: Ferrari is a big company, so every day you are in the media, for good or for bad.
"It can be possible the team is looking for another driver; you have some names on the line that maybe the team is looking at. And sometimes this is not helping the driver, and sometimes this is not helping even the team control the driver in the best way as well.
"But Ferrari is Ferrari, one of the biggest and most famous teams in Formula One. So definitely you have a lot more pressure there than maybe in another team."