Robert Kubica has revealed more details about why he decided against racing in the World Endurance Championship this year.
The 33-year-old Pole had two tests with the Manor LMP2 squad at Aragon earlier this year. He said the sessions in the British team's G60-LT-P1 "went quite well."
However, he subsequently decided against pursuing the option.
Speaking to Motorsport.com this week, Kubica explained exactly why he had decided against racing in WEC alongside his role as reserve and development driver at Williams F1.
"Mainly it was due to the time limitation," he said. "And because in the end I am quite busy with Williams.
"It was possible to do it," he added. "But it would mean that I would have had eight days at home in the space of five months.
"It was more the time, the amount of time that I could dedicate to this project. And I arrived to the point that after which I decided not to do it."
He dismissed suggestions that the decision was based on concerns about his physical health and stamina.
Kubica raced in Formula 1 until 2010 before suffering a major rallying crash which left him with life-changing injuries to his right arm.
"I think it would have been too much," he said. "It is better to concentrate on doing one thing properly than two things which might become risky if you don't do them properly.
"It is a shame I am not in a position to do Le Mans. But in the end I decided to concentrate on Williams."
Kubica said that his decision should not be taken as a reflection on the Manor squad. "The performance was not an issue," he said.
Last year, Kubica pulled out of a potential WEC drive for the ByKolles team after a terrible pre-season test.
"I had different situation with Kolles than with Manor," he stated. "In the end we agreed with Manor that I will do the test and I would decide after the test."
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