There are a limited number of reported cases of acute-onset isolated lateral compartment syndrome. We report a case of a 28-year-old recreational athlete who was erroneously diagnosed as having a muscle strain of his right lower extremity and discharged home. The patient over the course of the next day developed increasing leg pain and returned to the same emergency department where measurement of the peroneal compartment was 122 mm Hg. The patient had an emergent fasciotomy of the peroneal compartment of the right leg. The remainder of his hospital course was unremarkable. Although not commonly encountered, lateral compartment syndrome is important to consider in all patients who present with increasing pain out of proportion to injury and a tense swollen compartment after physical activity.