Regardless of how the signing was conducted, Arda Turan is now a FC Barcelona player and will remain so unless a president not named Josep Maria Bartomeu is elected and decides to exercise the option to send the Turk back to Atletico Madrid. But that is unlikely.
Arda has made a name for himself since joining the Madrid-based club in 2011, and since then he has become and influential midfielder/winger. Arda has become known as a workhorse, capable both in attack and defense, which is probably one of the main reasons Luis Enrique (allegedly) asked for him. Getting defensive contributions from his attacking midfielders and wingers is very important to Lucho, but let's first focus on Arda's attacking proves since joining Atletico.
In 177 appearances for Atletico, the Turkey international scored 22 goals and assisted on another 32, meaning Arda was involved a goal roughly every third game he appeared in. Arguably Arda's best season in Madrid came in the 2013-14 season, in which he was by far the most productive since leaving Turkey, scoring nine goals and assisting on another ten. While Arda' productivity dropped this past season, his influence on the pitch didn't. Actually, according to the stat sheet below, provided by SportsMatrix, his attacking contributions increased in certain areas.
Arda made more attacking actions than he had at any point in his Atletico career, 13.4% of all attacking plays the Rojiblancos made in the first two thirds of the pitch were made by Arda. For comparison, the average for a midfielder is around 11% and 8% for a winger. Perhaps more importantly, he also made the most good actions and lost possession the fewest times of his four year Atletico career.
While Arda's involvement in attacking plays improved this past season, so did his dribbling. Even though he couldn't reach the impressive "good" dribbles career high set in the 2012-13 season, he again managed to eclipse the 40% mark. The most notable improvement in Arda's dribbling came in the "bad" dribbles category, a category in which he has improved every single season since joining Atletico.
However, where Arda struggled the most this past season was in defense, where he set some of his Atletico Madrid lows and came close to that in some more areas. He recovered the least balls, only 2.7 per game, a steep drop off from nearly four in his first season in Spain, and his "good" defensive actions also couldn't reach his Atletico average. Arda might have improved on his "bad" actions compared to the Atletico league title winning campaign, but that number was still over 20%. If he could get that down to the high teens, like he did in his first two seasons in Spain, it would surely please his new coach. And fans too.