[...] they are in good shape to keep progressing with a wealth of draft picks, plenty of space under the salary cap and a young coach who has drawn raves in his two seasons. Of the players who were on the Celtics’ roster in Brad Stevens’ first game as coach in 2013 after leading Butler to NCAA title games in 2010 and 2011, only six remained in Sunday’s loss. [...] after trading point guard Rajon Rondo on Dec.