The Swede is unable to race at the United States Grand Prix on Sunday or at next weekend's Brazilian Grand Prix after the Leafield-based constructor was unable to continue trading and racing.
The announcement was made on the same day that Sutil produced the team's best qualifying performance of the season.
Ericsson told Sauber's official website. "The Sauber F1 Team has put its trust in me for 2015, and it makes me proud, as Sauber is known to be one of the best teams in developing young drivers.
"It will be a great challenge. I will give my very best to develop both as a driver, and to be part of the challenge to put the Sauber F1 Team back closer to the front where it belongs."
A team statement also revealed that the identity of their second driver will be announced at a later date.