Background: In sports, the risk of pathology or event that leads to an injury, a cessation of practice or even to an immobilization is high. The subsequent reduction of physical activity, or hypoactivity, induces neural and muscular changes that adversely affect motor skills and functional motor rehabilitation. Because the implementation of physical practice is difficult, if not impossible, during and immediately following injury or immobilization, complementary techniques have been proposed to minimize the deleterious impact of hypoactivity on neuromuscular function. Objective: The current narrative review aimed to discuss the contributions of motor imagery and action observation, which enhance motor (re)learning and induce neural adaptations in both healthy individuals and injured athletes. Methods: Online literature research for studies of the effects of motor imagery, action observation and their combination on hypoactivity, extracting relevant publications within the last decade (2009–2020). Results: From published studies and the authors’ knowledge of both motor imagery and action observation, some elements are provided for developing applied protocols during and after the immobilization period. Such interventions consist of associating congruent action observation with kinesthetic motor imagery of different movements, organized in increasing difficulty. The aim is to maintain motor functions and promote motor relearning by activating sensorimotor cortical areas and corticomotor pathways of the injured effector. Conclusion: This narrative review supports the implementation of combined motor imagery and action observation protocols in the context of sports rehabilitation.