Ten years ago, Dani Olmo made a difficult but important decision — aged 16, he left Barcelona, the club that had formed him, for Dinamo Zagreb in Croatia. It was a left-field choice but one that eventually led to Olmo, now 26, returning to Barca this summer in a €60million ($76m; £51.3m) deal after starring in Croatia and Germany, and with Spain as they lifted the European Championship.

The versatile attacking midfielder has made an encouraging start with Barca after registration issues delayed his debut. When he finally received clearance to play in La Liga, he came off the bench at half-time of their match against Rayo Vallecano and scored an 82nd-minute winner. In his second appearance, he scored again in a 7-0 demolition of Real Valladolid.

His return hit another stumbling block in September, though, with Olmo suffering an injury to his right hamstring in the win against Girona that ruled him out for around a month. He made his return as a substitute in the 4-1 thrashing of Bayern Munich on October 23, and played the final half hour of the brilliant 4-0 win against Real Madrid three days later.

This weekend, Barcelona face Espanyol, Olmo’s first club and their cross-city rivals. He will be up against his old friend Javi Puado, who he played with in the Barcelona academy and alongside when Spain won silver at the Tokyo Olympics in 2020. Speaking in the summer, Puado told Mundo Deportivo: “We have been roommates, we have gone on holiday together, we are good friends. I am sure we will see each other a lot this year but on the day of the derby. Knife between the teeth (laughs). I am happy for him, I know he was looking forward to returning home.”

Before Sunday’s game, The Athletic spoke to figures from Olmo’s time in Barca’s youth system, and at Dinamo Zagreb and RB Leipzig to chart the rise of a player who is enjoying a hard-earned Blaugrana homecoming…

Born in the Catalan city of Terrassa, where Barca’s legendary former midfielder and ex-coach Xavi is also from, Olmo arrived at their La Masia youth system aged nine from city rivals Espanyol.

Olmo was part of a talented Barca generation that included now Chelsea left-back Marc Cucurella and Getafe midfielder Carles Alena. He started as a centre-forward and was coached by Franc Artiga in the under-15 Cadete B team, scoring 18 times in 26 games.

“He was a very competitive player in training,” Artiga, who now coaches Russian side Khimki, tells The Athletic. “He was a hard worker, adapting to everything and you could see he enjoyed it. He comes from a football family, he has football in him and I’m sure when he came home, it was more and more football.”

When Artiga says Olmo is from a football family, he is referring to his father Miguel, a well-known youth coach in Catalonia who has managed teams including Girona and Sabadell in the Spanish second division. “Miguel is a mirror for young coaches,” says Artiga.

Olmo’s versatility was forged by necessity in those early years. A year before he worked with Artiga, Barca signed two South Korean youngsters, Lee Seung-woo and Jang Gyeol-hee. Lee was a centre-forward, meaning Olmo had to adapt.

“Lee was an exceptional player, one of the best I have coached, if not the best,” says Artiga. “It wasn’t an easy time for him (Olmo) or for the rest of his team-mates.

“He started playing centre-forward, and after Lee’s arrival he switched to playing on the right and left wing. In his last year, he had a very good season. With the FIFA sanction, the two South Koreans could no longer play and in a way that worked in his favour.”

The FIFA sanction in question was a ban from Barca signing players for two transfer windows after they breached rules on signing underage players from 2009-2013, including Lee and Jang.

“He (Olmo) returned to his natural position and had a spectacular year,” Artiga says. “(But) the fact that Lee was in the team made him alternate more positions and he became a very versatile player. He was very good at scoring goals, wherever he played.”

Quique Alvarez, Olmo’s last coach in Barca’s youth system with the under-16 Cadete A team, agrees. “He didn’t lose his ability to score goals, which was something he excelled at,” he tells The Athletic. “Maybe he wasn’t explosive as a winger, but he could adapt because he understood the game well.”

Artiga thinks those tough years competing for a spot in the team led to his decision to leave in 2014. He just couldn’t have predicted his destination.

“When I was told that Dani was not going to sign his first professional contract at Barca and that he was leaving, I thought the same thing as 90 per cent of the coaches who knew him: that he was going to go to England like most of those who left,” he says.

“When we were told he was going to Croatia, nobody understood.”

The surprise from Olmo’s coaches was understandable. As Artiga says, “He went somewhere that wasn’t for money, to a club that wasn’t superior to Barca. Time eventually proved him right.”

Olmo was determined to make it as a player and didn’t see a guaranteed path to the first team at Barca. He made the decision to move to Croatia along with his father Miguel after Dinamo Zagreb approached them.

They showed him a route to the professional game and pointed to the examples of other successful players who had developed there before moving to the elite, such as Luka Modric, Mateo Kovacic and Marcelo Brozovic. Olmo felt it was a good place to develop away from the spotlight of a major European league.

It was a tricky adaptation process at first. Olmo arrived with his mother, Dorita, who helped him settle. He did not speak Croatian and had to be taken under the wing of Luis Ibanez, an Argentine left-back who had been at the club since 2008 and supported him “like a little brother”, along with other South American players.

“The day he arrived, he was still a kid — I don’t think he had even finished high school,” Ibanez tells The Athletic. “He didn’t speak much, we tried to get him to adapt quickly to the team. We tried to make everything easier for him because arriving in Croatia at 16 was not easy. I remember I also arrived when I was 19 — the language is very difficult.”

Olmo’s father encouraged him to learn the language. He started with two or three classes a week while his experience in the dressing room helped him.

“In Croatia, they speak English very well but it’s not the same,” says Ibanez. “Dani was very smart to want to learn the language.

“That was a plus for him, to learn quickly and adapt to the team. Also being the person that he is — everyone loves him and he never has problems with anyone — meant the team welcomed him.”

He also took an interest in Croatian culture. The first match Dinamo played after Olmo’s arrival was in the eastern city of Vukovar, the site of a battle Croatia lost in 1991 after they declared independence from Yugoslavia.

Olmo wasn’t able to play yet but became interested in the conflict after seeing a memorial to those killed there, including some former Dinamo players, and read up on the history of the country. The one per cent of Olmo’s salary that he donates to the charity Common Goal goes to a project in Croatia that uses football to help war-affected communities.

Olmo joined Dinamo Zagreb in 2014 but had to wait until January 2015 to be registered with the first team as the club waited on documents from Barcelona. He had to show patience in the meantime, starting with Dinamo’s ‘B’ team.

“Everyone saw from the first moment that he was a very special player, so that wasn’t a question,” Dinamo’s then-technical director Davor Bukovina tells The Athletic. “The only question was when he was going to start playing with the first team.

“He started playing in our second team in the second division and he was absolutely the best player in the team. Then he got the chance to play in the first team and we all knew that a star was born.

“When he got the opportunity (to play for the senior side), he took it. And he became a player that we couldn’t imagine our first team without anymore.”

Olmo made his first-team debut in February 2015 and spent eight seasons with the side, winning nine trophies, including five league titles. He scored 34 goals and provided 28 assists in 124 games, starting as a left- or right-winger but mostly featuring as a playmaker.

“What he had and still has is his way of reading the game,” says Ibanez.

“He is one step ahead — before he receives the ball, he already knows what he is going to do. Sometimes players at his age (when he was at Dinamo) or younger want to get the ball and pass two or three players. He always tries to make it as uncomplicated as possible so he doesn’t lose the ball.”

His ability to adapt to the country and the language endeared him to supporters. The president of the Croatian federation and former striker Davor Suker even tried to naturalise Olmo for the national team before the 2018 World Cup, when he hadn’t made a senior appearance for Spain, but he preferred to continue playing for the country he had represented at youth level.

“All the fans loved him — and not only Dinamo fans, all Croatian people really respected him,” says Bukovina. “Because in every interview, he shows his love for Croatia and (says) that he will never forget the country and Dinamo Zagreb. That is something special, his connection to Dinamo Zagreb.

“I spoke to Miguel at the Euros final and I told Miguel, ‘I want him to play for Barca’. He told me to be calm, that the time would come at Barca or at some big team. And I told him, ‘No, he’s going to play for Barca because he’s a Barca player’.

“The other day, when he played his first game for Barcelona, I cried when he scored the winning goal. It made me very excited because for me he is a very special player — more like a son.”

That was yet to come, but first it was RB Leipzig’s turn.

Olmo had been on Leipzig’s radar before leaving Barcelona in 2014. He had been in their scouting database and was a player the club periodically evaluated at age-group tournaments and during youth league matches.

Once he made the transition to senior football, his suitability to Leipzig’s style of play quickly became apparent.

The club saw him as a player who wasn’t outstandingly quick, but who had a lightning-fast ability to read the game around him. Their data analysis showed he had a great sense for where space was on the pitch and how to progress the ball between the lines and towards the team’s attacking players as quickly and effectively as possible.

Dinamo’s asking price of more than €30million meant it was never just a technical decision. Leipzig are pitched somewhere between the true elite and the simply good — effectively a finishing school — and their model was and still is dependent upon selling players.

At 22, the club reasoned Olmo could not only develop and appreciate, but that his best attributes would stand out with their style of play. There was no reason he would not increase in value quickly and sharply.

The club were also convinced by Olmo’s experience. La Masia to Zagreb was an unusual path, but they believed that leaving his home country at 16 and encountering cultural change at such an early age would make a further adjustment to Germany relatively simple.

When Olmo arrived, Leipzig had an employee who served as his translator, but who also fulfilled a broader role, ensuring that he was not alone and helping him settle.

The adjustment between leagues was significant, but getting Olmo used to Leipzig’s physical requirements was another challenge. Reconditioning was a big part of his early months, as were gym sessions aimed at developing his core strength and durability for a more physical environment. There was an individual focus on Olmo’s work without the ball, a weakness that needed to improve for their pressing game.

Olmo made a strong first impression with club officials, who were struck by his professionalism. During that difficult transition period, he was often the first into Leipzig’s Cottaweg training facilities and the last to leave.

It was one of the reasons he was so quickly involved in the first team. After signing in January 2020, he made his debut against Borussia Monchengladbach on February 1 and started away at Bayern Munich eight days later. By the end of that pandemic-affected season, he had started back-to-back Champions League games, scoring a clever header in the win against Atletico Madrid in the quarter-finals before Leipzig were overwhelmed in the semi-finals against Paris Saint-Germain.

There were other factors in Olmo’s favour. Leipzig’s squad featured many young players at a similar stage of their career. Ibrahima Konate (then 21 years old), Dayot Upamecano (21), Nordi Mukiele (22), Konrad Laimer (23), Patrik Schick (24) and Christopher Nkunku (22) helped to create chemistry in the dressing room, allowing them to develop quickly under a coaching staff attuned to players of that age.

Staff at Leipzig, who spoke on the condition of anonymity to protect relationships, remember Olmo as a polite, smiley and cheerful personality who was always respectful of people at the club, regardless of whether they were directly involved with the first team. On the pitch, he was fierce — a winner who hated losing, even during small-sided games in training — and he showed palpable ambition.

But life in Leipzig suited him. He enjoyed the small city atmosphere and the respectful community. German people allow players to enjoy their lives without badgering them. He was fond of the city parks and their lakes and the opportunity to develop his career in quiet — until the point when he was ready to return to where it all began in Catalonia.