Rheal Cormier -- a longtime MLB reliever and a Canadian Baseball Hall of Famer -- died Monday after a battle with cancer, MLB confirmed.
He was 53-years-old.
The left-handed pitcher threw for several teams over his 16-year MLB career ... but had his most notable season as a pro with the Philadelphia Phillies in 2003, going 8-0 with a 1.70 ERA.
Cormier ultimately pitched for the Phils, Cardinals, Red Sox, Expos and Reds ... and finished his career with a 71-64 record and a 4.03 ERA.
Details surrounding his cancer diagnosis and subsequent battle with the disease are unclear .