By Alan Baldwin
LONDON (Reuters) - Kimi Raikkonen has pulled out of the last two races of the Formula One season in Texas and Brazil after deciding to have back surgery next week, the Lotus driver's manager said on Sunday.
The decision ended the 2007 world champion's two seasons with Lotus on a controversial note, with the Finn already warning the team a week ago that he could walk out if his wages were not paid.
Raikkonen is returning to Ferrari next year, the glamour team with which he won his world title, and had a seat fitting with them last week.
Manager Steve Robertson told Finnish newspaper Turun Sanomat and the autosport.com website that Raikkonen could no longer delay surgery.
"In an ideal world it would have been nice to finish the season with Lotus in the final two grands prix," he said.
"However, due to the severe pain that Kimi is having, sadly it is not possible."
The Turun Sanomat said he would have the operation in Salzburg on Thursday and would need four weeks to recover.
Raikkonen has a long-standing back problem, which flared up in Singapore in September and is understood to be a legacy from a crash he suffered in testing with Sauber during his 2001 rookie season.
However, he has also complained about Lotus's failure to pay his wages, telling reporters at this month's Abu Dhabi Grand Prix that he had received "zero euros the whole year".
The Finn added that he had considered not racing in Abu Dhabi, where he ultimately retired at the first corner after a collision having been sent to the back of the grid, and could skip the last two rounds if the problem was not resolved.
"You have to put the line somewhere and if it goes over that...it's not really my fault anymore," Raikkonen had said.
There was no immediate comment from Lotus, who have been trying for months to finalize an investment deal to secure the team's future.
The team have Italian Davide Valsecchi, last year's GP2 champion, as their reserve. If handed Raikkonen's seat for the last two rounds, he would be the first Italian on the grid since Jarno Trulli in 2011.
Mansoor Ijaz, chairman of a consortium of private investors that has said it wants to buy 35 percent of Lotus, told reporters in Abu Dhabi Raikkonen's situation had been resolved and he would be paid in full.
"I am confident that he will run the last two races and fulfill his professional obligations to us and to him," the businessman declared last weekend.
Lotus principal Eric Boullier also told reporters in Abu Dhabi that he was confident Raikkonen would race and the problems had been settled.
The team had also issued on Friday a preview for next week's race in Austin, quoting Raikkonen saying how much he was looking forward to it.
"After going there for the first time last year - like everyone - I'm particularly looking forward to this one. I like the American atmosphere, it's just a relaxed environment. They know how to have fun, and most of all they love racing," the Finn had said.
(Editing by Ed Osmond)