Nick Heidfeld lacked speed and therefore the ability to lead the Renault team as its top driver in 2011.
That was the claim of boss Eric Boullier at Spa-Francorchamps as he explained the decision to replace the veteran German with Bruno Senna.
Heidfeld, 34, is suing the team for breach of contract, and has been in the Belgian paddock this weekend in order to show the High Court judge that he is still ready to race the black R31.
"We did not bring him into this situation," argued Boullier to Auto Motor und Sport, "but as long as he is doing promotion for the team, that's ok."
Boullier said Heidfeld was signed to replace the injured Robert Kubica as the team's quickest driver with the most leadership skills alongside the less experienced Vitaly Petrov.
"He didn't get the car fast enough, so it didn't work for us," he told F1's official website.
Reuters quotes him as adding: "I was not very happy with the pure speed of Nick and his global performance as an experienced driver. That's it."
It's a risky decision, but if it's the chance to get back to the front, so be it
Boullier bristled when a reporter put to him that Heidfeld was only ousted because appointing Bruno Senna opened up lucrative sponsorship opportunities within Brazil.
"Bruno is a third driver and I guess it's logical that if we want to change our driver lineup that we promote our third driver. Full stop," he said.
Auto Motor und Sport quotes him as adding: "I think he (Senna) is better for the team and I expect that he can go at the speed of Vitaly in some time, maybe by Singapore.
"It's a risky decision, but if it's the chance to get back to the front, so be it. Of course, I get the blame if it does not work. But it's my job to make decisions."