Knicks Add to Their Training Camp Roster The Knicks added three new players Tuesday to its training camp roster. The team signed free agents in guard Oscar Bellfield, center Henry Sims and forward Mychel Thompson. The Knicks also signed forward John Shurna on Monday to a partly guaranteed deal. Thompson, who is 6-foot-6, is the lone player in the group with N.B.A. experience. He played for the Cleveland Cavaliers last season. In his five games, three of which he was the starter, he averaged 3.6 points, 1.4 assists and 1 rebound. Thompson was also on the Knicks' summer league team three months ago. In Las Vegas, he averaged 5.6 points and 3.4 rebounds. Bellfield, Sims and Shurna each finished his college career last season. Bellfield, a 6-foot-2 guard who played at Nevada, is the career assists leader in the Mountain West Conference with 582. He averaged 9.8 points and 5.4 assists last season. Sims, who is 6-10, averaged 11.6 points and 6 rebounds at Georgetown last season. Shurna led Northwestern with 20 points a game last season and holds the record for most points in team history with 2,038. The Knicks now have 19 players under contract for training camp. As of now, the team has one remaining spot available for the 14-man roster when the regular season starts. Chris Copeland and Chris Smith, the younger brother of J.R. Smith, have also signed nonguaranteed contracts with the Knicks.