Paget-Schroetter syndrome, more commonly called "effort thrombosis," has been well documented in the literature but is considered an uncommon cause of morbidity in the athletic population. We describe a case of axillary-subclavian vein thrombosis ("effort thrombosis") that presented as painless arm swelling in a high school football player. This case reviews the presentation, diagnosis, and management of this difficult problem in a young athlete.