This article presents a novel ankle rehabilitation device based on a reconfigurable parallel mechanism with a circular rail. The 1-PS/3-RRRRR architecture of the mechanism provides its moving platform with 3-DOF spherical motion and allows adjusting the vertical position of the motion center. First, the paper discusses motion capture experiments, carried out to estimate the desired rotational angles in the ankle joint. Next, the obtained results are used to develop a computer model of the ankle rehabilitation device. CAD simulations show the proposed mechanism provides the dorsiflexion/plantarflexion in the range from \(-50^\circ \) to \(+30^\circ \) , inversion/eversion in the range from \(-30^\circ \) to \(+30^\circ \) , and unlimited adduction/abduction.