Trying NOT to get promoted, Its a strategy some managers use to strengthen their teams through development of training and matches by holding their team back for a few seasons and it also helps them save up tokens, the downside to that is playing the waiting game by playing a number of seasons in the same Level before making any advancements on the game so it actually takes longer to win promotions but it can make winning league/champions league easier by having good players for a few seasons.
Its not possible not to gain skill points as players have to play at least 1 match per day and if no training was done then they would be on full condition and they would gain progress.