First NFL, now MLB? Boston University researchers say Ryan Freel suffered from chronic traumatic encephalopathy before he committed suicide last year. Freel is the first professional baseball player to be diagnosed with CTE, a degenerative brain disease. "The real important issue is that he hit his head multiple times—small hits, big hits, in baseball and outside of baseball," a BU researcher said. CTE can be caused by multiple concussions and has been linked to suicides, most notably in the case of linebacker Junior Seau. It turns out football and hockey aren’t the only dangerous sports.