Thyroid hematoma secondary to blunt trauma is uncommon, and no consensus exists for its management. We describe the case of a 46-year-old man who presented with neck swelling after he had sustained a blunt-trauma injury to his neck while playing soccer. Imaging revealed a large mass consistent with a thyroid hematoma. The patient was admitted for observation and followed up with serial imaging. He was eventually discharged without surgical intervention. However, he later underwent a thyroid lobectomy to treat compressive symptoms and for cosmetic reasons. Pathology revealed that the patient had a papillary thyroid carcinoma, which might have predisposed him to the hemorrhage. Thyroid hematoma secondary to blunt trauma has been documented in normal thyroid glands and in glands with preexisting benign pathology, but to the best of our knowledge, no report associating this condition with a thyroid carcinoma has previously been reported in the literature. A neoplasm should be suspected in a case of thyroid hematoma that fails to resolve with conservative treatment. The management of this condition is surgeon- and case-specific, and the overall prognosis is good.