Tim Raines not only played ball, he also battled lupus
When playing for the Oakland Athletics in 1999, Tim Raines experienced extreme fatigue which prompted him to seek medical attention. Raines had swelling in his knees and 15 lbs overweight. When his doctor ordered a biopsy on his kidneys, Raines was diagnosed with lupus. He had a severe case that attacked his kidneys, but he was able to treat it with radiation therapy and medication. Raines went back to playing baseball with the Montreal Expos in 2001, and retired with the Marlins in 2002.
Photo source: Tim Raines by Arturo Pardavila III