Multiple computed tomography (CT) scans are required to diagnose lumbar spondylolysis stage and confirm fusion degree. However, multiple CT scans should be avoided because of radiation exposure. There are no case reports of complete diagnosis and treatment of pediatric lumbar spondylolysis without the use of CT. Fast field echo resembling a CT using restricted echo-spacing (FRACTURE) is a magnetic resonance imaging (MRI) sequence used to evaluate bone lesions. Here we report the case of a pediatric patient with lumbar spondylolysis who was able to return to sports after diagnosis, treatment, and bone union confirmation using MRI and FRACTURE.