def get_save_points(position, player_id, minutes, df_saves):
    """Returns average save points scored by player_id when playing minutes minutes (or
    zero if this player's position is not GK).

    df_saves - as calculated by fit_save_points()
    """
    if position != "GK":
        return 0
    if minutes >= 60:
        if player_id in df_saves.index:
            return df_saves.loc[player_id]
        else:
            return 0
    else:
        return 0