premise: Derek Ervin Smith (November 1, 1961 – August 9, 1996) was an American professional basketball player. He won a national championship with the Louisville Cardinals in 1980, and spent nine years in the NBA in a career shortened by a knee injury. He would later become an assistant coach for the Washington Bullets from 1994 until his death.
hypothesis: Derek Ervin Smith hurt his arm playing basketball. 
reason: It said he had a knee injury but at some point he may have hurt his arm, too. Or he may not have. There's really no way to know because it may have healed.  