The Boston Herald's Mark Coffman says you can pencil rookie Joe Johnson in as the Celtics' starting shooting guard.  Johnson will give the team a reasonable third scoring option, something they didn't have last season.  The Celtics are not bringing back any of the competion.  The last player to fall off their list is Bryant Stith.  The C's have offered him a one-year contract, but both sides know it won't be accepted.  The Celtics probably will keep their 15th roster spot open for the next while so they have greater roster flexibility.