Symptomatic thoracic disc herniation is clinically rare. There are few cases of disc herniation of the thoracic spine in top athletes described in the literature. We herein present a rare case of chest wall pain due to thoracic disc herniation in a professional baseball pitcher. A 30-year-old, left-handed pitcher complained of left-sided chest wall pain in the region of his lower ribs during a game. Neurological examination revealed hypoesthesia of the left side of the chest at the level of the lower thoracic spine. Magnetic resonance imaging (MRI) of the thoracic spine showed a left-sided paramedian disc herniation at the T9-T10 level. The player was initially prescribed rest, administration of pregabalin (150 mg twice a day), and subsequent physical rehabilitation. He was able to resume full training and pitching without medication 6 months after the onset. A follow-up MRI of the thoracic spine showed a reduction in the size of the herniated disc compared to the initial findings. Though relatively rare, thoracic disc herniation should be considered in cases of chest wall pain in athletes.