Max Chilton admits that he is facing a "very emotional weekend" as he prepares for the Russian Grand Prix.
The 23-year-old will provide Marussia's solo drive in Sochi, with the decision having been made to run only one car as a mark of respect for Jules Bianchi.
Bianchi is in a critical but stable condition having suffered a severe head injury in Japan last week.
"I don't know how to put into words how truly devastated I am by what has happened to Jules," Chilton said in a short statement. "The support from the F1 family has been incredible and all we can do is be there to support Jules' family at this difficult time.
"It is going to be a very emotional weekend for the whole team, but we will try to get through it and keep praying for Jules."
Alexander Rossi was initially named as a reserve driver ahead of this morning's first practice session, although Marussia opted to run with just one car.