It’s been a funny season for Arsenal.

Unai Emery began his tenure with back-to-back defeats to Manchester City and Chelsea but then went on a 22-match unbeaten run to get themselves back into the top-four.

Since a shock defeat to Southampton exactly a month ago, it’s been tough for the Gunners.

A League Cup quarter-final defeat to Spurs, a drab draw against Brighton, a 5-1 hammering against Liverpool and Saturday’s 1-0 loss to West Ham have all occurred in the past 30 days.

Suddenly, Arsenal are six points off the top-four and level on points with Manchester United.

Just as well the January transfer window has opened and Emery can sign a few players, then.

Well, that’s not going to happen.

"We cannot sign players where we have to make a payment ... we can only make loan signings,” Emery confirmed last week.

But why?

Well, it was thought that the decision was financial. But according to Gabriel Marcotti from ESPN, that’s not exactly the case.

The money is there. After all, Arsenal were ranked sixth in the most recent Deloitte Money League and have made a profit every year since 2008.

The report explains how Arsenal “offer a case study of how big decisions from newcomers, made in a short time, can have massive knock-on effects.”

WHY ARSENAL WON'T LET EMERY SIGN ANYONE

And it all happened 12 months ago.

Arsene Wenger may have been in charge but it was all change elsewhere.

The club’s longtime transfer negotiator Dick Law had left, so had chief scout Steve Rowley.

Chief executive Ivan Gazidis - who has now left for AC Milan - brought in Raul Sanllehi as a de facto director of football and Sven Mislintat as chief scout.

Gazidis, Sanllehi and Mislinat immediately had three massive decisions to make.

They had to sell Alexis Sanchez, give Mesut Ozil a new contract and sign a new forward.

While the club-record £57.6 million signing of Pierre-Emerick Aubameyang was a risk that has paid off brilliantly, the other two decisions have been something of a disaster.

The decision to sell Sanchez to Manchester United coincided with the arrival of Henrikh Mkhitaryan on a deal worth more than £10 million a year through to 2021.

The Armenian has since started just 18 league games in 12 months and has been hugely disappointing.

Ironically, Ozil has also made the exact number of league starts over the same period.

And the decision to bump the German’s contract from £9 million to £20 million-plus per year now looks ludicrous.

Emery clearly doesn't fancy Ozil and has often left him out of matchday squads this season.

To put the three decisions into context, the club committed more than £150 million over the next three-and-a-half years in wages to Mkhitaryan, Ozil and Aubameyang. That’s roughly one-fifth of the club’s entire wage bill for players that were 28, 29 and 29 at the time.

The report concludes that it was the rushed decisions of Gazidis, Sanllehi and Mislintat a year ago that means Emery won’t be allowed to make the same mistake.

“They got one of those decisions right [Aubameyang] and, it appears for now, two wrong. But the choices made a year ago are making a lasting impact, both in the type of players Arsenal can recruit and in the ones they can retain.”