Marussia will run only one car for this weekend's Russian Grand Prix as a mark of respect for Jules Bianchi.
The 25-year-old is in a critical but stable condition in hospital following a severe head injury sustained in Japan last week.
Alexander Rossi was named as a reserve driver ahead of today's first practice session, although Marussia have opted to run with just Max Chilton for Sunday's race.
"We will run a single car for the duration of the forthcoming Grand Prix weekend in Sochi, out of respect for our driver Jules Bianchi, who remains in hospital in Yokkaichi, Japan, in a critical but stable condition," the F1 team announced in a statement.
"We have written to the Stewards of the Meeting to inform them that we have withdrawn our second car. Notwithstanding the presence in Sochi of Alexander Rossi, the nominated Official Reserve Driver for the 2014 Russian Grand Prix, the team feels strongly that fielding a single car, that of driver number 4, Max Chilton, is the appropriate course of action under the difficult circumstances of the weekend.
"Jules' car crew have built a second car, which has been scrutineered and is ready to race, and this will remain on his side of the garage throughout the weekend. In support of Jules and his family, the Team and its cars will carry the familiar #JB17 graphic, to ensure that although Jules is not with us in Sochi this weekend, he is, nonetheless, racing on with the Marussia F1 Team."
The first practice session of the Russian Grand Prix gets underway at 7am this morning.
