Sauber will continue to nurture Sergey Sirotkin over the next season with the view of handing him a race seat in the future.
The teenager joined the Hinwil squad in July on the back of a sponsorship agreement with three Russian entities and, at the time, it was announced that he would drive for Sauber in 2014.
However, the team have confirmed Adrian Sutil and Esteban Gutierrez for next year with Sirotkin named as test driver.
Team principal Monisha Kaltenborn, though, says they will continue to support the youngster and help him to gain his Superlicence as quickly as possible.
"We have been working with Sergey since August, and he has been able to gain more and more insight into Formula 1," Kaltenborn said.
"Now he is taking the next step towards the top level of motorsport in his new role as test driver.
"Our experience of him is as a very focused, calm, and talented driver.
"Now we will continue to support him, including obtaining his Superlicence. Our goal remains to prepare him for a debut in Formula 1."
The 18-year-old, whose highest level of motorsport experience is the Formula Renault 3.5 Series, believes this move will help him to prepare for the eventual step into the F1 world.
"It's a big chance for me to become the test driver for the Sauber F1 team," said Sirotkin.
"I will work hard to improve myself and to extract the maximum out of this opportunity.
"Formula 1 is very complex, so it is important to get an opportunity like this.
"My main focus next year, however, will be the World Series by Renault, which is very competitive.
"This will give me the chance to prepare even better in order to be ready for the next big step."
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