Unai Emery’s side lost the Europa League final to Chelsea and finished fifth in the Premier League.
It means the north London side will now enter their third consecutive season outside Europe’s elite.
This has not stopped them being linked with a mega-money for Zaha.
The forward, who scored 10 goals and made 10 assists for Palace last year, commands an £80millionfee.
And Emery has also been linked with a move for £20-million Ligue 1 star William Saliba.
But Swiss Ramble, a Twitter channel that specialises in football finances, has revealed why the club could struggle to make these signings.
In a thread, they showed the north London side made £70million profit before tax in 2018.
They also said: “However, this profit was driven by £120m from player sales, so Arsenal actually made a hefty £42m operating loss in 2017/18.
“That’s a £94m decline from the previous season’s £52m operating profit.
“This was due to the “double whammy” of no Champions League and a surging wage bill.”
And the Twitter channel went on to make a worrying prediction for the season ahead.
Swiss Ramble added: “In fact, given that there were no major player sales in 2018/19, it is highly likely that Arsenal will report a large loss before tax for last season.
“It would be the first time the club will have slipped into the red since 2002.”
Several charts show how the Gunners have been overtaken by Liverpool and rivals Tottenham in revenue over the decade.
And they also revealed the club had the worst revenue performance in 2018, falling by £30million from the previous year.
The Twitter channel also made a worrying claim about the club’s new Adidas deal.
“The new Emirates and Adidas deals adding an extra £40m a year,” Swiss Ramble wrote.
“The problem is that the other clubs are not standing still, so their deals will also increase.”
“Given that there were no major player sales in 2018/19, it is highly likely that Arsenal will report a large loss before tax for last season”
The thread has received thousands of likes since being posted earlier today.
But the Gunners faithful were left with a sinking feeling.
“This has f***ed me right off,” one supporter said.
Another commented: “A painful read.”
While a third simply said: “Jesus.”