There were 42 goals in the Premier League at the weekend, a bumper crop that, with 16 more in five midweek games, took the average goals per game this season to 2.73. With Luis Suárez and Daniel Sturridge in devastating form, Manchester City hammering teams all over the place and Fulham shipping hatfuls every week, this has felt like a season of glut.

It is not, though: 2.73 goals is lower than last season's average of 2.80 goals per game in the Premier League, which in turn was lower than the 2.81 of 2011-12. In fact, if things go on as they are, this will be the lowest scoring season since 2008-09. Still, there does appear to be an overall pattern suggesting more goals are being scored. Between 2000-01 and 2008-09, there were no Premier League seasons in which there was an average of more than 2.7 goals per game. This looks like being the fifth in the row that beats that mark.

In part it is down to a change in the laws. The tweaking of the offside rule has increased the effective playing area, which has allowed the sort of diminutive creative player who might previously have been bullied out of games to return – although the way Bayern Munich and Borussia Dortmund swatted aside Barcelona and Real Madrid in the Champions League semi-finals last season seemed to hint at a return to greater athleticism – combined with high technical ability – at the very highest level.

Similarly the crackdown on tackling from behind and intimidatory play, a process that has been going on over the past two decades, has encouraged self-expression in central areas.

Watching Arsenal's dismal resistance at the weekend, or the shambles of Cardiff against Liverpool, the catalogue of mistakes in Tottenham's 3-2 win against Southampton or even the thrilling chaos of el clásico, it is tempting to suggest teams have forgotten how to defend.

That is something that is very difficult to examine statistically, given good defending often results in nothing happening – think of Peter Shilton saying that he barely touched the ball in some of the best games he had for Nottingham Forest because he had organised his back four so well he did not have to – but because of the increased attacking onus on full-backs and the way that out-and-out defensive midfielders have all but vanished from the game, it is logical that should be the case.

The decline of the defensive midfielder – where are our David Battys, our Claude Makélélés, our Frankie van der Elsts of yesteryear? – seems particularly marked this season. Barcelona pioneered the trend, using their real holder, Javier Mascherano, as a central defender. Bayern off-loaded Luiz Gustavo and now field a passer – Philipp Lahm, Javier Martínez or Thiago Alcântara – in the role. Bayern and Barça, though, defend primarily by keeping the ball; possession for them becomes a proactive means of goal prevention. For teams who are less good at dominating the ball, the wisdom of gambling with a ballplayer rather than a ball-winner is less clear.

Arsenal, for reasons best known to Arsène Wenger, having acquired a true midfield battler in Mathieu Flamini, have stopped playing him in key games (Arsenal in Premier League games in which Flamini has played more than 45 minutes this season: W12 D 2 L 1; in which he has not: W7 D4 L5). City loaned out Gareth Barry, leaving an occasionally uneasy partnership at the back of midfield between Yaya Touré and Fernandinho. Liverpool have Lucas Leiva fit again but tend to play Steven Gerrard in the deep role, enhancing the quality of long passes out from the back but at the expense of cover for the back four.

Only two teams in the Premier League stand aloof from the trend.

Chelsea, eschewing the high defensive line of the majority of Europe's elite, have thrived since José Mourinho, in the aftermath of the Capital One Cup defeat by Sunderland, decided to revert to his preferred reactive approach.

Since then – bolstered by the arrival of Nemanja Matic, a true defensive midfielder who also happens to be able to pass (as opposed to passer who can do a bit of covering) – Chelsea have conceded only five times in 15 league games.

The other Premier League side who have proved that defending is possible within the modern laws is Crystal Palace. In the first 12 games of the season, Palace conceded 21 goals; in the 18 since Tony Pulis has taken over they have let in 18 (a process that began with Keith Millen, under whose caretaker charge Palace conceded four in four).

The problem is that in those 18 games Palace have scored only 12, the defensive resolve perhaps coming at the expensive of attacking flair (although given they scored only seven in the first 12 games, it seems fair to say there was not a huge amount of flair to begin with).

The vast majority of other sides, though, have followed the pattern started in 2009. The example of Blackpool – who, although they were ultimately relegated, showed it was possible to compete with attacking football – has perhaps encouraged teams nearer the bottom not simply to sit back and look to soak up pressure. Blackpool went down in 2010-11, since when relegated teams have averaged 43.22 goals per season; in the five seasons before that the figure was 34.07.

The Blackpool paradigm, coming two years after the step up in average goals per game, did not begin the trend but it does perhaps sustain it.

Sides from top to bottom, it appears, have opted for a balance that favours attacking.