How would Ronald Koeman utilise the current Barcelona squad?

For those who don't know, Ronald Koeman is a former Barcelona defender who was one of the important players in the all-conquering team of Johan Cruyff. Presently, he is the manager of the Netherlands football team and has also managed teams like Everton, Southampton, Valencia, Ajax and Feyenoord. He is mainly known for his work with Everton and Southampton.

Before jumping into answering how Koeman would utilise the current Barcelona squad, let's understand his tactics and how his teams play.

Philosophy:

Having played under Cruyff, Koeman is an ardent believer of positional play, popularly known as 'tika-taka' football. He has successfully managed to implement this intricate style of football even with an average squad of Everton. Furthermore, he likes to develop young players and integrate them into his team. The likes of Holgate, Davies and Calvert-Lewin at Everton, and De Ligt, De Jong and Dumfries at the Netherlands have thrived under Koeman and got many opportunities in his team.

Tactics:

Koeman majorly plays in a 4–3–3 formation but is flexible enough to tweak it into 4–2–3–1 and 3–4–3 between games.

In his 4–3–3 formation, following is what can be observed:

Centre-backs: When he has a good defence with him (Netherlands), he likes to keep a high defensive line and encourages his centre-backs to involve themselves in the build-up. Moreover, his centre-backs also attempt a lot of long balls.
Fullbacks: From his teams like Everton and the Netherlands, it can be observed that he likes his fullbacks to keep making attacking runs forward but he doesn't want them to indulge much into their possession game and wants them to stay wide. In short, he likes attacking fullbacks but doesn't prefer inverted fullbacks (like Alba).
Midfield: His midfield is what that interests me the most. During his time with Everton and the Netherlands, he always likes his holding midfielder to dictate the tempo of the game. Morgan Schneiderlin at Everton and Frenkie De Jong were both the heartbeat of their teams. As for the other two midfielders in his midfielders, he wants one midfielder to cover the ground a lot & also help out defensively and the other midfielder to be able to tweak between a central midfielder and an attacking midfielder.
Wingers: As for his wingers, he likes his wingers to cut-in and drift into central areas now and then. Another interesting thing that can be observed is that his right-wingers at both Everton (Barkley) and the Netherlands (Bergwijn) often drop deep and create chances. This particular thing would suit Barcelona a lot as a certain Argentinian also plays like this. As for his left wingers (Mirallas at Everton and Babel/Promes at the Netherlands), they play like how David Villa used to play for Barcelona at left wing: cutting inside and often becoming a second striker for the team.
Striker: As for his striker, he is flexible and can play with a poacher and even with a false nine. Lukaku as a poacher with Everton played his best football under Koeman and Depay as a false nine with the Netherlands has also been thriving under Koeman.

This following image showing average positions of the Everton team will further help in relating to the above points:

Coming to the original question, Koeman would actually be able to utilise this squad pretty well. Following things will be observed if he takes over the current squad:

High paced and expansive football. Unlike Valverde, Koeman's tactics would liberate the players and remove the shackles of the players. The transition from midfield to attack will be quick and effective.
More vertical passing. Under Valverde, this Barcelona team is often accused of passing too horizontally and ineffective possession of the ball. The things, however, would change under Koeman and there would be a lot of vertical passing with an emphasis on effective use of the ball.
Semedo as the undisputed right back. Ever since Semedo arrived at the Camp Nou outfit, he has been battling with Roberto for the right-back position with Valverde failing to identify his prefered right back. However, as conveyed above, Koeman likes his fullbacks to make marauding runs forward but not participate as much in the build up. Koeman will clearly prefer Semedo over Roberto as the latter, contrary to the former, isn't pacy and likes to constantly involve himself in the build-up.
Better Busquets. “But hey, Busquets is already world class!” Agreed, he is already world class, but he has been better. With Koeman's tactics, Busquets would become the motherboard of the Barcelona supercomputer. He would be the one to set the tempo of the team and would control the possession.
Resurgent Coutinho. Although Coutinho's dismal form this season is majorly because of himself, Coutinho hasn't been playing in his prefered position: attacking midfielder. While even Koeman's tactics wouldn't separately have an attacking midfielder position, as conveyed above, Koeman likes to tweak his formation into 4–2–3–1 between the games very often. This might suit Coutinho and we might see him performing according to his usual standards.
Development of young players and more opportunities for them. As evident from his time with Everton and Netherlands, he clearly likes to develop young players and integrate them into his plans. Valverde, one the other hand, has failed to use the brilliant squad at his disposal and has not wisely rotated his players. If Koeman is appointed, the talented crop of players like Alena, Malcom, Todibo and other highly talented La Masia youngsters will grow as players and would certainly get more opportunities with the first team.

This is how Barcelona under Koeman would possibly line-up:

Conclusion:

Even though Barcelona have extended Valverde's contract, there is no doubt that he hasn't been able to play the beautiful and intricate football Barcelona is known for and if results don't support him, the impatient board may fire him. Koeman, as explained above, is a worthy candidate and should be seriously considered for currently, he is one of the very few managers who can bring back 'the true Barca' to the frustrated Cules.

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