Tampa Bay Rays Minor League pitcher David Hess says he is starting chemotherapy to treat a cancerous tumor in his chest.

Hess said that he went to an emergency room about a week ago after experiencing chest tightness and shortness of breath.

"After some scans, blood work, and time at the hospital we learned that I had a cancerous germ cell tumor sitting in the center [of] my chest pressing majorly against my heart and lungs," he wrote. "Today we got the final diagnosis and treatment plan that has chemo starting up on Monday to shrink and hopefully eradicate the tumor entirely."

He finished this year with Triple-A Durham, where he was 6-2 with a 3.57 ERA.