The NBA 2K14 video below reveals the team rosters of the current 30 NBA teams and overall ratings for every player in the game. All the ratings seen in the footage were taken from the base roster of the game, accurate as of September 20, 2013. This is the roster that you'll see when the game comes out on October 1st.
2K Sports promised to constantly release new rosters through Dynamic Living Rosters. This new feature will update the player ratings and attributes (shooting %, pass, rebounds, steals, blocks, 3pts, dunks etc.) daily based on their real-life performances.