Renault team manager Flavio Briatore says Jarno Trulli was made to leave the team in deference to the rest of the staff.
Briatore accused Trulli of having his mind elsewhere after five races without scoring a point. The Italian left the team and was replaced by Canadian Jacques Villeneuve at the Chinese Grand Prix, but the former World Champion failed to shine and finished in 11th place.
Briatore said Trulli's commitment was not 100 per cent and he had to fire him.
"I had to fire Trulli out of respect for the people who work at our team," Briatore told Gazzetta dello Sport. "At Renault everyone gives 100%, and if a driver shows up lazy, he won't have anything to do with us anymore.
"I don't know what was on Jarno's mind but I only looked at his performances, and they were not satisfactory anymore, hence off he went."
Trulli said the car was to blame for his poor performances and claimed on Wednesday Villeneuve's result in China proved him right.