Arsenal's Sokratis Papastathopoulos quickly becoming the most reliable pillar of defence

In a season of considerable flux further up the pitch -- a campaign of tweaked formations, uncertain positions and half-time substitutions -- Arsenal's defence has been surprisingly consistent under Unai Emery. It has proved either resistant to shiny new signings like Bernd Leno or Stephan Lichtsteiner or, in the case of Sokratis Papastathopoulos, the back four has congealed around an influential new face who will be sorely missed if his absence is confirmed this weekend.

In the Premier League, Arsenal's defence and goalkeeper have remained intact since the second game of the season, when Nacho Monreal was ready to resume first-team duties. Petr Cech, Hector Bellerin and Shkodran Mustafi are the only Arsenal players to have played every minute of the campaign so far. Monreal hasn't missed one since slotting in and Sokratis would have joined the group but for the injury which forced him off against Everton last weekend.

As Arsenal sweat on the fitness of their summer signing ahead of the weekend's game against Watford it is worth reflecting how quickly, and how impressively, Sokratis has made himself into an essential member of Emery's team.

His elevated status is somewhat surprising. It is fair to say that the purchase of a 30-year-old Greek centre-back was met with considerable scepticism: five months after Liverpool had smashed a world record to wrench Virgil van Dijk from Southampton for £70 million, this was hardly a statement signing indicative of an imminent football revolution at Arsenal.

And so it has proved. Arsenal's defence is still their fatal weak point, all too often shapeless and rudderless. But setting the systemic failings aside for a second, the individual performances from Sokratis are a notable crumb of comfort.

He isn't a spectacular libero or an all-action hero in the Sergio Ramos mould, but Sokratis has brought some much-needed seriousness to the Arsenal defence. Supporters probably expected some of the no-nonsense moments we have seen, and relished the moment when he enthusiastically told Mustafi exactly what he had done wrong in the buildup to his own booking against Everton at the weekend, but the early matches of the season have revealed some hidden qualities, too.

First, the pace which saw him place third in an internal speed test in August, behind only Bellerin and Pierre-Emerick Aubameyang; pace which was showcased a fortnight later when he made a vital recovery challenge following a mistake by Mustafi in a 2-1 win away at Newcastle. Supporters notice these moments and it was the first inkling that Sokratis might be more rounded and impressive a player than some had suspected.

Another such insight came in the 4-2 home win over Vorskla Poltava in the Europa League on Sept. 20. On 74 minutes, Sokratis meandered forward and dinked a lovely little ball into the right channel for Lichtsteiner, whose cross was turned home by Mesut Ozil. A positively Hlebian pre-assist. Arsenal fans have enjoyed seeing a surprisingly accomplished defensive talent emerge: arguably the most successful of the club's summer signings at this stage, though Lucas Torreira may ultimately prove more consequential.

With Laurent Koscielny not fit until November at the earliest, Konstantinos Mavropanos injured for four weeks and Calum Chambers farmed out to Fulham on loan, the worry over Sokratis' fitness is pronounced. Especially with the two upcoming matches against Watford and Fulham sandwiching an 8,000-mile round trip to Baku to face Qarabag in Europe. It's early in the season for a defensive crisis.

But even if Sokratis has assumed impressive importance this early in his Arsenal career, it does not necessarily follow that he will be happy with his start to life in England. As he said on the day he signed, he lives for clean sheets. "I like that my team doesn't [concede] goals and I like the zero in the defence of course," he said. "I will do everything to help achieve these goals."

As we know, Arsenal only managed to get their first clean sheet of the season in Sunday's somewhat fortunate 2-0 win against Everton and even then, Sokratis was off the pitch due to his injury. Emery clearly has a lot of work ahead of him before he can feel confident in his defence, but in Sokratis he already has a player he can count on. If only he is fit.