Wenger's back three ploy could be doomed if Arsenal lose at Anfield
Arsene Wenger is a creature of habit. In two decades with Arsenal, certain patterns and trends have emerged, whether it's lifting the occasional cup or finishing fourth.
Until last season, a back four was another staple of Wenger's management. However, back in the spring a desperate roll of the dice saw him introduce a new-look three-man defence. The change in formation sparked an upturn in Arsenal's fortunes, as they embarked on an impressive run that culminated in them lifting the FA Cup at Wembley.
However, old habits die hard. In each of Arsenal's first two Premier League fixtures this season, Wenger has switched to a back four partway through the game. A close look at his transfer activity this summer suggests he might well be looking to revert on a permanent basis.
There was no such clue in preseason. Wenger spoke to journalists about wanting to experiment with both a back three and a back four in friendlies, but invariably Arsenal lined up with three centre-halves.
It made sense to continue with the new shape. Arsenal's players had responded brilliantly to the change -- perhaps they had in part been instigators of it? With the security of an extra central defender, Arsenal appeared to play with more conviction and crucially, a greater degree of tactical security.
However, Wenger has always been loath to give too much credit to Arsenal's switch in formation. Speaking in April, he suggested it was merely a matter of shifting focus.
"What [the change in formation] did was it got the players to focus on something that is concrete, to forget anxiety and a little bit of uncertainty," he said.
"Sometimes when a team doesn't do well, just focusing on something different helps to focus on something that might be better."
He's never sounded particularly convinced by lining up with three centre-halves. Wenger is guided by his aesthetic principles, and must feel torn about employing a formation with a significant defensive emphasis. He's wrestled with that in recent weeks, using full-backs instead of centre-halves and permitting his midfielders to charge forward with alarming abandon. The results -- a disappointing 1-0 loss at Stoke and conceding three goals at home to Leicester -- have been far from ideal.
It's telling that when Wenger needs a goal, he instinctively returns to his preferred back four. Sometimes it results in fielding players wildly out of position -- Hector Bellerin as a left-back springs to mind -- but there is something about the pattern of play produced by a back four he finds irresistible.
Some of Wenger's other recent decisions suggest he is not exactly wedded to the new system. Arsenal started the season with a healthy clutch of centre-halves, but since then Gabriel Paulista has been sold and there are reports suggesting Calum Chambers could soon follow him. What's for certain is that the Englishman hasn't yet been involved in one of Wenger's match day squads this season. Against Stoke, Rob Holding also found himself excluded from the 18. Wenger is not exactly treating his centre-halves as precious commodities.
Per Mertesacker was not trusted to play in the Potteries, and now reports suggest the Gunners could be willing to entertain Inter Milan's bid for Shkodran Mustafi. Is Wenger contemplating letting another centre-back go because he knows he only intends to use two in his team from some point soon? Conventional wisdom about having two players for every position would then suggest he would needs just four in his squad, rather than six.
A back four would solve some problems for Wenger. It would enable him to deploy Bellerin and Sead Kolasinac as an impressive set of attacking full-backs, as well as offering him to restore the once undisputed first-choice defensive pairing of Mertesacker and Laurent Koscielny. However, what presumably appeals more is the opportunity to introduce another attacking player: Wenger could squeeze Alexis Sanchez, Mesut Ozil and Danny Welbeck (or perhaps even Olivier Giroud) in alongside new boy Alexandre Lacazette.
In some respects, it feels like Wenger is waiting for an excuse to revert to type. This weekend, Arsenal travel to Liverpool needing a positive result to prevent their season sliding into an early crisis.
It's surely too soon for the Arsenal manager to discard the shape which saved his skin last season. However, defeat against Liverpool will only accelerate what feels like an inevitable switch back to Wenger's comfort zone.
James McNicholas is one of ESPN FC's Arsenal bloggers. You can follow him on Twitter @gunnerblog.