I'm going to modify my suggestion and say that each owner can nominate 10 total players with a top limit of 3 of his own offensive players and 3 of his own defensive players.
That way if someone doesn't want to nominate anyone from their own team, they can nominate 10 players from other teams.
That way if someone doesn't want to nominate anyone from their own team, they can nominate 10 players from other teams.