Like most managers, Arsene Wenger has made his fair share of mistakes in the transfer market. The likes of Christopher Wreh, Igor Stepanovs and Francis Jeffers instantly spring to mind.
Perhaps the most disappointing addition of Wenger's tenure at Arsenal was Jose Antonio Reyes, who joined the Gunners from Sevilla in the winter of 2004 for a fee of £10.5m, with a potential £7m added on.
Regarded as one of the brightest prospects in Spanish football, the 20-year-old was expected to take the Premier League by storm.
He certainly started life at Highbury brightly, scoring twice to knock Chelsea out of the FA Cup and going on to make 13 appearances as 'The Invincibles' secured the Premier League title.
However, during the following campaign his form became inconsistent and despite signing a new six-year contract in 2005, rumours were rife that Reyes yearned for a return to his native Spain.
The attacker got his wish in 2006 when he joined Real Madrid on a season-long deal, before he secured a permanent move home eight years ago today. Yet, it would not be Los Blancos that he joined, but their city rivals Atletico Madrid on a deal thought to be worth around £5m.
A short statement on Arsenal's official website read: "Everyone at Arsenal thanks Jose Antonio for his contribution to the club and wishes him the best of luck for the future."
Meanwhile, the player, who had scored 23 goals in 110 outings for Arsenal, added: "I'm happy again at the club I wanted to join. Real wanted me right up until the last moment, but Atletico made a great effort to get me.
"The club have been interested in me a long time and tried to sign me from Sevilla when I was 13. I owe it to them."
Reyes went on to have four years on the books at the Vicente Calderon, one of which was spent on loan with Portuguese club Benfica.
Then, early in 2012, he returned to his boyhood club Sevilla, where he remains on the playing staff to this day.