Both Arsenal and Barcelona have struggled in their own ways in recent times. Irrespective of that, they remain two of the biggest clubs in Europe.The Spanish giants have witnessed a difficult phase overall, especially after the departure of Lionel Messi in the summer due to financial issues. Their on-the-pitch troubles still persist and remain a concern for this season.Arsenal and Barcelona have traded players regularlyArsenal, on the other hand, are facing a torrid time and finding it very difficult to qualify for the Champions League over the past few seasons. Their identity as a big club is taking a hit with time and it is necessary that they step up very soon.The north London club have been involved in many transfer deals with Barcelona over the years. The deals saw some top players going to the other side but overall it is the Catalan club who have attracted more than the other way around. On that note, let's take a look at the high-quality players who left the Gunners to play for the Spanish giants.#5 Alexander HlebAlexander Hleb was a key player under Arsene WengerOne of the most underrated and versatile players to play at Arsenal under Arsene Wenger has to be Alexander Hleb. The Belarusian midfielder was signed from VfB Stuttgart in 2005.Hleb, with his sharp passing, creative abilities and amazing work-rate, was an asset on the field. He was capable of playing almost anywhere in midfield. His impressive performance with the Gunners attracted interest from Barcelona.Gooner Chris@ArsenalN7 Alexander Hleb appreciation tweet. The Belarusian dribbling maestro was an absolute magician with the ball at his feet, he was poetry in motion. One of the most underrated footballers of all-time. Arsenal Legend 4:32 PM · Jan 29, 20226021875🇧🇾 Alexander Hleb appreciation tweet. The Belarusian dribbling maestro was an absolute magician with the ball at his feet, he was poetry in motion. One of the most underrated footballers of all-time. Arsenal Legend ⚪️🔴https://t.co/2FlALiOSKAHaving played three seasons with the London club, Hleb joined the Catalan club. After winning the Treble in the 2008-09 season, he struggled with game-time at the club. This led to multiple loan spells for the Belarusian before he left in 2012.#4 Alex SongAlex Song should have stayed with the GunnersArsenal signed Alex Song on loan from Bastia for the 2005-06 season and made the move permanent the following season. With the Gunners, the Cameroon midfielder grew into one of the best midfielders in the Premier League then.His excellent reading of the game, amazing anticipation and fine passing abilities made him the perfect player in deep midfield. His fine performances encouraged Barcelona to go after his signature and they were successful in doing so in 2012.Mark K Twain@SocietyNews@brfootball Representing voice of Arsenal Barcelona players, Alex Song had this to say: "I met Barca's sporting director, and he told me I wouldn't get to play many games, but I didn't give a f***. I knew that now I would become a millionaire. I wanted to rub shoulders with the big boys."8:54 PM · Feb 3, 2022281@brfootball Representing voice of Arsenal ✈️ Barcelona players, Alex Song had this to say: "I met Barca's sporting director, and he told me I wouldn't get to play many games, but I didn't give a f***. I knew that now I would become a millionaire. I wanted to rub shoulders with the big boys." https://t.co/vjcFZl40seUnfortunately, the move didn't turn out to be that productive for Song as he struggled to start ahead of Sergio Busquets. A two-season loan move to West Ham United, followed by a permanent move to Rubin Kazan, ensured a disappointing spell at Barcelona.