A novel concept for the deflection of rotating asteroids is presented, based on the conversion of the asteroid rotational kinetic energy into translational kinetic energy. Such conversion is achieved using an orbital siphon, a tether-connected chain of masses, arranged vertically from the asteroid surface, which exploits the rotation of the asteroid for the delivery of mass from the asteroid to escape. Under the conditions to be discussed, the siphon can be initiated to ensure self-sustained flow of mass from the asteroid to escape. This mechanism is proposed to use a fraction of the asteroid as reaction mass, with the asteroid rotational kinetic energy leveraged to deliver the mass to escape and hence impart a reaction on the asteroid itself. Key parameters, such as velocity change, deflection duration, tension requirements and siphon length, are discussed. Deflection effectiveness is assessed for different release strategies. It is shown that typical velocity changes on the order of 1 cm/s can be achieved within a time window of a decade.