Renault team owner Gerard Lopez has admitted he is disappointed with Nick Heidfeld.
"We expected more from him," the Genii Capital chief is quoted as saying by Brazil's Globo Esporte.
German veteran Heidfeld, 34, was signed by the Enstone based team at short notice this year to replace injured regular Robert Kubica.
There is now speculation that Renault is considering replacing him with Bruno Senna or Romain Grosjean.
"I have mixed feelings about Nick," Lopez explained. "We have to recognise the great contribution he made at the beginning of the season.
"He helped us to develop the new exhaust system which was not easy to understand. It gave us a clear direction in the development of the car.
In terms of results, there is no doubt that we expected more from him
"Now, in terms of results, there is no doubt that we expected more from him and (we) are disappointed."
Globo Esporte reported that the Renault team, whose owner Genii is collaborating on a $10 billion investment with Brazilian company WWI, is considering running Senna in November's season finale at Interlagos.