In master-slave teleoperator systems used for tele-rehabilitation purposes, the passivity can be violated because of the assistive actions of a therapist; moreover, any type of passivation approach to the design of such a system would defeat the purpose of the assistive therapy. In this paper, a design framework is presented that does not rely on passivity considerations. A number of results are given that deal with stability and transparency properties of the tele-rehabilitation system in the case of intrinsically non-passive behaviour of the therapist. In particular, a stabilization scheme for the networked tele-rehabilitation system is proposed which guarantees stability regardless of the specific actions of the therapist. Simulation results are presented which confirm the theoretical developments.