Sauber on Wednesday confirmed that Nico Hulkenberg is moving from Force India to join the team in 2013.
But, with Sergio Perez heading to McLaren next year, the Swiss team left the future of the Mexican's current teammate Kamui Kobayashi in doubt.
As for German Hulkenberg, "We've been observing Nico for some time now and his performances have been very persuasive," team boss Monisha Kaltenborn said.
The 25-year-old debuted for Williams in 2010, famously capturing pole in Brazil before being dropped by the famous British team.
He returned to F1 as Force India's reserve last year, stepping up to the race seat in 2012 as Paul di Resta's teammate.
"I'd like to thank the management at Force India for giving me the chance to return to Formula One as a team driver," Hulkenberg said on Wednesday.