Atletico Madrid had Julio Diaz for eight years. In February 2026 they handed him a full La Liga debut. Five months later they let him go to Sevilla with no direct fee and kept 50 percent of his future rights. That isn't how clubs treat a player they've written off. It looks more like a hedge: Atletico couldn't promise him minutes, but they didn't want to lose out if he turns into something.
That makes the 21-year-old left back worth a closer look. His story isn't loud. It's a steady climb through youth teams, one memorable European week, one full senior debut and a long contract in Andalusia.
Diaz at a glance
| Full name | Julio Diaz del Romo |
|---|---|
| Born | January 10, 2005 (age 21) |
| Birthplace | San Fernando de Henares, Madrid, Spain |
| Height and weight | 174 cm (5 ft 9 in), about 70 kg (154 lbs) |
| Position | Left back, can also play left wing |
| Preferred foot | Left |
| Club | Sevilla FC (since July 2026) |
| Contract | Until June 30, 2031 |
| Previous club | Atletico Madrid and Atletico Madrileno |
| International | Spain Under 18, Under 19 and Under 20 |
| Market value | Around 1.5 million euros (database estimate, early 2026) |
Rayo first, then Atletico at 13
Diaz grew up in San Fernando de Henares, a town just east of Madrid. His first academy was Rayo Vallecano's. In 2018, at around 13, he moved across the city to Atletico Madrid, and that switch shaped everything after it.
He went up the age groups in the usual order: Under 15s, the Under 17 B side, then Juvenil A, Atletico's Under 19 team. He was never the academy's headline name. Coaches valued him for being reliable. He defended well, he was willing to run forward from left back, and he got a little better every season. Academies produce plenty of flashier teenagers who fade. Players like Diaz often last longer.
The week Europe noticed
The 2022 to 2023 UEFA Youth League was where people outside Madrid started to notice him. Playing for Atletico's Under 19s, Diaz was voted the second best player of the group stage. Full backs rarely get that kind of recognition at European youth level. Forwards and number tens usually take the attention.
The next season brought a trophy. Diaz was a regular starter in the Juvenil A side that won the 2023 to 2024 Division de Honor Juvenil title, and he contributed in both boxes. After that he moved up to Atletico Madrileno, the reserve team in the Primera Federacion, Spain's third tier.
He spent two seasons there, 2024 to 2025 and 2025 to 2026, wearing the number 34 shirt. He made around 50 appearances in all competitions and scored his first goal for the reserves in April 2025. Third-tier football is physical and unforgiving, and it is a fair test of whether a young defender can handle adult opponents. Diaz played regularly, which tells you he could.
Ninety minutes at the Carlos Tartiere
On February 28, 2026, Diaz started a La Liga match for Atletico Madrid at the Estadio Carlos Tartiere and played the full game in a 1 to 0 away win. Clubs often give a young debutant twenty minutes and take him off. Atletico gave him ninety. The club's own announcement called him one of the reserve team's most consistent players and praised his quality and versatility.
The deal: no fee, half the future
On July 28, 2026, Sevilla announced his signing. As reported, no direct transfer fee was paid, and Atletico kept 50 percent of his future rights. If Sevilla sell him for good money, Atletico take half. Levante were also reported to be in advanced talks, but Diaz chose Sevilla and signed until June 30, 2031.
For Diaz, the logic is simple. Breaking into Atletico's first team at left back is very hard, and a five-year contract at a La Liga club gives him time to develop. For Sevilla, the risk is low: a youth international with top-flight experience who cost nothing up front. The weak point for Sevilla is the resale value. Developing a player well and then giving away half the profit is a trade-off they accepted, and it will only look like a good one if he becomes a regular starter.
A wide player in a full back's shirt
At 174 cm, Diaz is not built to win every header at the back post. His value is elsewhere. Scouting reports describe an attack-minded left back who is quick, technically tidy and comfortable further up the pitch. He can play left wing as well as left back. That flexibility is useful for a squad player. It also leaves an open question: will a coach see him as a defender who attacks, or a winger who can defend? How Sevilla answer that this season will say a lot about his future.
Pay and net worth: estimates, not facts
There are no official salary figures. At Atletico Madrileno, his wage was reported at around 567 pounds a week, which is normal for a reserve player at a big club. His Sevilla terms have not been made public. A first-team contract in La Liga should be a clear step up, but we won't guess at a number.
Icon Polls estimates Julio Diaz's net worth in 2026 at between $500,000 and $1 million. This is a rough estimate based on his club earnings and bonuses. Football databases put his market value at around 1.5 million euros in early 2026. That figure is a valuation, not money he has earned. Both numbers will likely rise if he becomes a regular in La Liga.
Starting for Spain in Chile
Spain's youth coaches have trusted Diaz for years. He played for the Under 18s in 2022. He then earned around 10 to 12 caps for the Under 19s between 2023 and 2024, and 7 for the Under 20s in 2025. The highlight was starting at left back for Spain at the 2025 Under 20 World Cup in Chile. Our count puts his total youth appearances at roughly 30.
A senior Spain call-up is still a long way off, and Spain has plenty of options at full back. For now, Diaz's job is to win a place at Sevilla. If you'd like to compare today's prospects with the greats, you can vote for the best football players of all time on Icon Polls.
Three quick answers
How old is Julio Diaz?
He is 21. He was born on January 10, 2005, and turns 22 in January 2027.
Did Sevilla pay a transfer fee for him?
Reports say no direct fee was paid. Atletico Madrid kept 50 percent of his future rights as part of the deal.
Which positions can he play?
He is mainly a left back but can also play as a left winger. He is left-footed, and his versatility is one of the qualities Atletico highlighted.
