Many keeper leagues, as well as some single season leagues, have adopted salary cap rules similar to the NHL. In a "Salary Cap League", a salary is assigned to each player before the manager selects his team. Salaries are usually determined by the NHL player's real salary. Otherwise a number value is assigned - usually by an online hockey pool program - or it is determined through an auction process. Each manager must ensure that they do not go over the predefined salary cap when selecting players.