After conceding 51 goals during the 2018/19 season - Arsenal desperately needed to improve defensively last summer.
With Laurent Koscielny walking out of the door, the Gunners turned to the experience of David Luiz.
Luiz certainly isn’t the most reliable defender in world football and Chelsea were more than happy to hand him over to their London rivals at a fee of £8 million.
However, a recent report from Amy Lawrence from The Athletic has revealed the true cost of the deal.
She writes that on top of the £8 million fee, Arsenal “paid £6 million to intermediaries to fix everything up” as well as his £10 million-a-year salary.
It means that Luiz has cost Arsenal up to £24 million for one year of service.
With the Gunners conceding 36 goals in their 28 matches so far this season, they’ve probably improved ever so slightly at the back.
But has he really been worth £24 million of their money? Certainly not.
Luiz is now 33 and Arsenal have a decision to make. Do they offer him an extension to his £10 million-a-year contract or allow him to leave on a free transfer?
If he was to leave, Mikel Arteta will have to rely on Shkodran Mustafi and Sokratis Papastathopoulos - who both have one year remaining on their contracts themselves.
Meanwhile, Rob Holding and Calum Chambers are returning from long-term injuries. Pablo Mari is expected to make his loan move to the Emirates permanent while William Saliba will arrive this summer after being allowed to stay at St Etienne for a further year.
But even if he’s offered an extension at Arsenal, it seems Luiz is eyeing up a return to Benfica.
In fact, earlier this week, he admitted to speaking to Benfica president over a potential move.
"I have already spoken with (Luiz Filipe) Vieira. It will happen if the President permits it and fans want me back," Luiz admitted.
"To be able to wear that jersey again and enter the stadium is worth more than many trophies. Benfica doesn’t deserve me to come back without helping."