NORTH MELBOURNE coach Dean Laidley saw up close against St Kilda on Saturday night the infectious value of tough love with your team and your standards.

After the game, he warned his side of a similarly stringent line with some of his senior players after the team insipidly sacrificed a 33-point lead to be overcome by the Saints.

Laidley promised that senior names would be among those who felt the pain of a loss that, after a win against Hawthorn the previous week raised finals expectations, had seriously jeopardised the club's chances of a place in the eight.

"We talk about mental toughness being your ability to act in critical moments and some of our guys can't do that, so we're going to introduce some new guys to do that," he said.

Ultimately, Laidley said, it was his midfield that let the side down.

"We can't rely on Adam Simpson being as brave as he was; we need his understudies being consistent and they are not," he said.

"We need to make sure we don't stand for that as a football club."

Laidley would not elaborate on whom he had in mind — and North Melbourne would no comment yesterday — a decision for confidentiality that will doubtless ripple through the group all week and leave some who should not be concerned for their place in the side likewise troubled that they may be vulnerable.

It would appear from the match that Corey Jones, who has endured a terrible season and who has struggled with injury, may be one who endures a Dal Santo-and-Milne-like visit to the VFL.

Jones was well beaten on Saturday night by Jason Blake and simply could not find the football. He took two marks and did not kick a goal.

Fellow forward Nathan Thompson also had a dreadful night, with only six touches and two marks.

One of those marks was a towering grab in a pack, which had the potential — should he have converted the mark into a goal — to lift his side as it struggled to withstand the Saints' onslaught. Thompson's shot registered a behind, his only score of the night.

The Roos forward line, save for Matt Campbell and Lindsay Thomas, has struggled to gel almost since the time Aaron Edwards went down with injury.

A fortnight ago, Laidley unleashed a blistering post-match attack on midfielder Daniel Harris, reportedly raising the spectre of the security of his future at the club.

Harris responded against Hawthorn with an outstanding display and acknowledged how stung he had been by Laidley's rebuke.

On Saturday night, Harris had 15 touches, which in a congested game of high possession — both sides had 360-plus touches — was insufficient.

Of no doubt is that Laidley was not referring to Brent Harvey, captain Simpson or wingman Daniel Wells, who all showed class undimmed, when he spoke of a tough line with some senior players this week.