During spring training, Galarraga developed a sore back. Treatment from the team's trainers and team doctor included hydrobaths, massages, muscle relaxers, and stretching, but would not stop the nagging soreness. Galarraga was referred to a medical oncologist in Atlanta for a thorough physical exam and an MRI. When the diagnosis came in, the famous Galarraga smile disappeared. On the second lumbar vertebra in his lower back, Galarraga had a tumor known as non-Hodgkin's lymphoma, a form of lymphatic cancer. He missed the entire 1999 season receiving chemotherapy treatments. Rockies third baseman and ex-teammate Vinny Castilla switched briefly from his traditional number 9 to number 14 on his jersey, to honor Galarraga's cancer fight.