A BLIP on the radar or an issue that requires Craig McRae's full attention?

Over the last month, Collingwood has gone from being the League's most vaunted and watertight defensive side to having the leakiest backline in the competition. And by some distance.

Up until round 19, the Magpies were conceding just 68.5 points per game. It was clearly the fewest of anyone in the League. But, over the last four weeks, that number has since ballooned to 105.8 points per game. It's the most of anyone.

For context, even West Coast (89.8 points per game) and North Melbourne (90.5) are conceding less in this stretch. Meanwhile, only Essendon (103) and Richmond (105.2) are also conceding a triple-figure average within this period.

As part of that run Collingwood has shipped scores of 105 to Hawthorn, 101 to Geelong and 124 to Brisbane. It's the first time in more than 15 years the club has conceded three consecutive scores of 100 points or more.

Clearly, personnel issues have played their part. Darcy Moore missed over the weekend with a hamstring injury, Jeremy Howe has been trialled in the forward line, while important midfielders Nick Daicos and Jordan De Goey have also been absent.

Midfield issues have subsequently played an important role in Collingwood's recent defensive problems. Over the last month, Champion Data notes that the Pies rank dead-last for contested possession differential and No.11 for inside-50s conceded.

Further highlighting the midfield problems, Collingwood has also gone from being the AFL's best side for defending scores from stoppage (26.3 points) up until round 19, to ranking second-last over the last month (43.5 points).

The Pies have also gone from ranking No.1 in the competition for defending scores from turnover (38.8 points) up until round 19, to ranking third-last over the last four games (56.3 points).

But the problems, to a certain extent, have been two-fold. Collingwood is now giving up more opportunities, but the club is also having more problems in defending those opportunities.

For example, Champion Data notes that Collingwood's goals against per inside-50 percentage has risen from 19.5 percent (No.1 in the AFL) to 29.9 percent (last in the AFL) over the last month.

The opposition's shot at goal accuracy has also risen from 41.7 percent (No.1 in the AFL) to 58.7 percent (last in the AFL) across the last four weeks, which can often suggest the opportunities generated are coming from more dangerous areas.

Its defensive-50 pressure rating has dropped from 204 points (No.7 in the AFL) to 183 points (last in the AFL) over the last month, while its opponents are retaining the footy on 50.8 percent of kicks going inside-50 (which ranks No.16 in the AFL) in that period.

It all paints a slightly worrying, if not totally reparable picture, for McRae's side. Yes, the recent numbers are bad. But the club remains first on the ladder, one game clear of Brisbane with one match still to play in the home-and-away season.

The overwhelming 'good' might still outweigh the club's month of 'bad'. But the stats depict a series of trends Collingwood will want to rectify as it looks to surge towards the premiership it has long been eyeing in season 2023.

A blip or a worry?