Sauber team principal Monish Kaltenborn has praised the team's re-hiring of Jorg Zander, calling it "a very important step".
Zander was previously a member of the team during its BMW guise and will rejoin the team having left Audi Sport in th3e wake of their World Endurance Championship departure.
"We are honoured that we have convinced such a renowned and experienced technical leader to be part of our team and plans for the future," Kaltenborn is quoted by F1i.
"This is a very important step for the implementation of our strategic goals, in order to guide the team into a new and successful era. Zander fits well into our team, he has a lot of know-how in Formula 1, as well as in motorsport in general."
"As technical director he will have the overview as well as the responsibility for all technical departments."
"In our factory in Hinwil he will have the possibilities to work technically at a very high level. We are convinced we will make progress with him. We wish him a good start on his return to Sauber, for which we ensure him our full support."
Bahrain International Circuit - Winter testing