Nick Heidfeld and Bruno Senna now appear to be in a straight fight to replace Robert Kubica in the Lotus Renault F1 team this season.
Kubica is recovering from a serious rally crash last week and will not be taking part in the upcoming Formula 1 campaign, so the Lotus Renault team are on the lookout for a replacement.
Senna, Heidfeld and Vitantonio Liuzzi were initially all in line for the drive but now the team have confirmed it will be either Senna or Heidfeld who gets the place, with the pair to be evaluated during the Jerez test, which starts on Thursday.
A Lotus Renault statement read: "Lotus Renault GP has revised its driver line-up for this week's test session in Jerez de la Frontera, Spain.
"Vitaly Petrov will drive the R31 on Thursday and Friday, as originally scheduled.
"For Saturday and Sunday, the team will give mileage to Bruno Senna and will also evaluate Nick Heidfeld, who is a potential replacement for Robert Kubica as a race driver."
Senna, who along with Romain Grosjean was one of Lotus Renault's test drivers for the coming campaign, is the outsider to get the nod with Heidfeld, who has been in the sport since racing for Prost in 2000, expected to be confirmed as Kubica's stand-in next week.