Peterborough boss Graham Westley says poor discipline is costing them dear.
Posh have amassed 100 yellow cards and seven reds in league games this season - the most in the top four divisions.
"A lot of our cards are sloppy cards, situations where players will stick out a leg rather than work a little bit harder," said Westley.
"The discipline of a group of young players is something that often needs managing. There's no question our discipline is short of the mark."
Westley replaced Dave Robertson as Posh boss in September with the club 18th in the table and lifted them into the play-off places before a run of one win in 11 league matches saw them drop off the pace.
They are now 14th in the League One table, and he told BBC Radio Cambridgeshire: "You don't win titles or promotions with poor discipline.
"It costs you too often in games, you can't afford to be down to 10 men however many times we've been down to 10 men and win games consistently. You can't afford the suspensions.
"But more than that you need the work ethic, focus and concentration that goes with discipline. So we've been nipping it in the bud on the training ground and next year the level of discipline has to be a strength of ours rather than a weakness."
The ex-Stevenage boss is confident that a summer of change will bring positive results next campaign.
"My learning as a manager is that when you go in and stamp your authority things can go one way or the other for you," he said.
"If you take things a little more slowly, you've probably got a better chance of making sure you succeed in the long term. I've come in here and changed very slowly and tried to let things run and observe, and gradually make changes.
"The summer time is the perfect opportunity to get things sorted out. I know what I think needs changing here and I think if we make some big changes over the summer we'll see a much different performance level next year."