The team principal told reporters: "We have very high expectations and both of them know that. We have two young, very fast and talented drivers.
"As for Nico we have been watching him last year and we know well how fast he is. We think he is a very efficient driver which means if he gets the opportunity he takes it and brings the result home.
"We feel it is time to bring him into F1 and I am confident Gutierrez will contribute to the success of the team."
Sauber finished sixth in the constructors' championship in 2012.