Former Cubs closer Lee Smith dealt with serious health problems this summer that almost cost him his life.

The Hall of Famer underwent a life-saving heart transplant back in July, according to former Chicago Tribune writer Fred Mitchell.

Smith suffered from shortness of breath and lost over 100 pounds, initially thinking it was cancer that was causing the issues. But then he discovered his heart was not functioning as it should, which led to a transplant.

He was diagnosed with amyloidosis, which is a rare disease that impacts organs like the heart or liver.

Smith, who turns 67 in December, spent the first 8 seasons of his 18-year career with the Cubs. He appeared in 458 games in Chicago, saving 180 with a 2.92 ERA.

Check out more on Smith’s harrowing story on Fred Mitchell’s personal website.