This single-subject case study was conducted as a part of a randomized trial investigating the efficacy of mechanical diagnosis and therapy (MDT) and spinal thrust manipulation (STM) in patients who meet a clinical prediction rule (CPR) for spinal manipulation. Following initial examination, a patient who met the CPR was treated initially with STM and then eventually with MDT. The Oswestry Disability Questionnaire (ODI), Fear-Avoidance Beliefs Questionnaire, and the Numerical Pain Rating Scale (NPRS) were administered at the initial examination and at a two-week follow-up. Data were analyzed based on changes in the pain rating scale, ODI, and straight leg raise scores from initial examination to discharge. In accordance with a study protocol in which the patient was part of, this patient was changed from STM to MDT after the second physical therapy visit due to failure of overall improvement. The patient received MDT during the third session and continued with this approach until discharge. This patient responded favorably to MDT presenting with a 20 degrees improvement in SLR on the left and 10 degrees on the right, 6 points lower on the NPRS, and a 4% decrease on the OSW after a total of 6 visits.