Kubica's car shows severity of crash
Bruno Senna, Vitantonio Liuzzi and Nick Heidfeld are in the frame to replace injured Renault driver Robert Kubica.
Hospitalised Kubica faces more surgery on multiple fractures after a rally crash in Italy, which Renault say will keep him out for at least two months.
"We will look for Kubica's substitute: the names considered are Senna, Liuzzi and Heidfeld," said Renault's team principal Eric Boullier on Tuesday.
BBC Sport understands that Heidfeld has been in talks with Renault on Tuesday.
Heidfeld's camp would make no comment on the 33-year-old German's future in F1.
KUBICA STATS & FACTS
Former team: BMW Sauber
Born: 7/12/1984, Krakow
F1 GP debut: Hungary 2006
Doctors have suggested that it could take Kubica, who is likely to remain in hospital for two to three weeks after Sunday's crash, up to a year to recover fully.
The Pole was
operated on for seven hours by two teams of surgeons
after being airlifted to a hospital near Genoa.
"The team is close to Robert, we wait for him with open arms and we hope he can come back before the end of the season," added Boullier.
Senna - who raced for the Hispania team for much of last year - is the first reserve at Renault, while Liuzzi and the highly experienced Heidfeld are looking for a seat after losing out at Force India and Sauber respectively.
Renault say they will not be making any announcements on the driver line-up for the four day-test which begins in Jerez this Thursday.
The team would only confirm that Russian Vitaly Petrov would resume his driving duties as normal.
Kubica's right hand was partially severed in the high-speed crash, and he also suffered arm and leg fractures after his car hit a church wall.
Initial reports suggested he was in danger of losing his hand, although those fears were later played down.
Renault said the general condition of Kubica - who is one of F1's most talented drivers - had continued to improve overnight.
"On Thursday, Robert should undergo some more surgery in order to stabilise the fractures to his right shoulder and right foot," said the Lotus-backed team in a statement.
"Three or four days later, another operation will allow his elbow fracture to be stabilised as well.
"According to the doctors, the levels of inflammation are in the norm considering his medical condition, and the recovery of his forearm remains encouraging.
"Yesterday [Monday], Robert was able to talk to his doctors and relatives. His medication makes him sleep quite a lot, but he is responding to all external stimulation."