This paper presents additional evidence showing the persistent functional deficits in concussed athletes as revealed by altered movement-related cortical potentials (MRCP) preceding whole body postural movements at least 30 days post-injury. Eight student-athletes participated in this study (a) prior to injury; and (b) 3, 10 and 30 days after MTBI. EEG was recorded while subjects produced static balance tasks and dynamic postural movements. All subjects were cleared for sport participation within 10 days post-injury based upon neurological and neuropsychological assessments as well as upon clinical symptoms resolution. There was a persistent reduction of MRCP amplitude prior to initiation of postural movement up to 30 days post-injury, although abnormal postural responses basically recovered within 10 days post-injury. The frontal lobe MRCP effects were larger than posterior areas. This supports the notion that behavioral symptoms resolution may not be indicative of brain injury resolution. Overall, persistent alteration of movement-related cortical potentials after MTBI may indicate residual disturbance of neuronal networks involved in preparation and execution of postural movements and a lower threshold for brain re/injury.