Thoracic outlet syndrome (TOS) most commonly manifests in overhead athletes (e.g., baseball pitchers, swimmers, weight lifters) due to nerve compression caused by skeletal abnormalities. We present the case of a 43-year-old recreational runner with unilateral upper extremity pain while running. Vascular imaging identified an aberrant subclavian artery origin with positional compression in the absence of cervical bone anomalies confirming arterial TOS. A first rib resection and anterior scalenectomy led to symptom resolution. This case emphasizes the importance of a broad differential and complete workup in non-overhead athletes presenting with symptoms consistent with neurogenic TOS, as vascular interventions may be necessary to prevent future complications.