Plenty of La Liga full-backs arrive through the front door: a big academy, a smooth climb, a debut everyone saw coming. Oso took the side entrance. He bounced through four youth setups, was moved out of an attacking role in Sevilla's reserves, and only made his first-team debut at 20. By the summer of 2026, Premier League and Serie A clubs were being linked with him. That is a quick turn for a player most neutral fans couldn't have named two years earlier.
His real name is Joaquin Martinez Gauna. He is 23, left-footed, and plays on the left side of Sevilla's defence. The interesting part isn't just where he is now. It's how unlikely the route was.
Oso in brief
| Detail | Information |
|---|---|
| Full name | Joaquin Martinez Gauna |
| Known as | Oso |
| Born | 9 July 2003, Torrevieja, Alicante, Spain |
| Age | 23 |
| Nationality | Spanish and Argentine |
| Height and weight | 1.83 m (6 ft 0 in), about 70 kg (154 lbs) |
| Position | Left-back, also left wing-back or left midfielder |
| Preferred foot | Left |
| Club and shirt | Sevilla FC, number 19 |
| Youth clubs | Algorfa, Kelme, Real Murcia, Malaga |
| Senior clubs | Atletico Malagueno, Sevilla Atletico, Sevilla FC |
| Contract | Runs to June 2027 (as reported in summer 2026) |
| Reported market value | Around 10 million euros (mid 2026) |
| FC 26 rating | 72 overall, 80 potential |
| @osoooo19 |
An Argentine household on the Costa Blanca
Torrevieja is a seaside town in the south of Alicante, a long way from Buenos Aires. Oso was born there to Argentine parents, which is why he holds both Spanish and Argentine nationality. Football in the house leaned south. He has talked about his father raising him on River Plate, and about getting up at four in the morning in Spain to watch their matches live.
That detail says more than any scouting note. Kids who sacrifice sleep for a team on another continent tend to be the ones who stick with the game when it gets difficult. Football runs in the family too: his brother, Gabri Martinez, plays for UCAM Murcia B.
From grassroots to Malaga, then the call from Sevilla
His early football came at small local sides, Algorfa and Kelme, before spells in the academies at Real Murcia and then Malaga, which he joined in 2018. He made his senior debut for Atletico Malagueno, Malaga's reserve team, in October 2021, and scored his first senior goal against UD San Pedro in April 2022.
Three months later Sevilla signed him on a three-year deal. He started with Sevilla Atletico in the Segunda Federacion, and his first-team debut came in the Copa del Rey in December 2023. In February 2024 the club renewed his contract through June 2027, a sign they rated him before most of the league had noticed.
From 2024/25 his minutes with the senior side grew. In 2025/26 he made around 27 appearances across all competitions, with 2 goals and 3 assists. For a full-back still learning top-flight football, that's a respectable return, and it puts his senior career tally at roughly five goals, reserve football included.
The positional switch that made him
Oso wasn't always a defender. He played further forward as a youngster, and it was at Sevilla Atletico that coaches moved him to left-back. It looks like the right call. The skills that made him a decent attacker (pace, a willingness to run at people, delivery from wide) are exactly what modern teams want from their full-backs.
What he does well, and what still costs him
He's direct. Give him space and he goes, either to whip in a cross or to try his luck from distance. He also takes a decent free kick, which isn't something you can say about many full-backs. At 1.83 m he has enough height to compete in the air, while a lean frame keeps him quick along the touchline.
The defensive side is still a work in progress, and it would be dishonest to pretend otherwise. Scouting reports have flagged:
- Tackling technique and timing
- Positional discipline when the ball switches flanks
- Passing accuracy
- Keeping the ball under pressure
None of that is unusual for a converted attacker in his early twenties. His energy and willingness to get back help cover some of the gaps. Whether he closes them will decide if he's a solid La Liga full-back or something more.
A summer of suitors and a shrinking contract
The sharpest change has been his price. Football data platforms put his value at around 200,000 euros in June 2025; by mid 2026 the commonly cited figure was about 10 million euros. His release clause at Sevilla has been reported at 20 million euros.
The contract is the complication. With his deal set to run out in June 2027, reports during the summer 2026 window suggested a fee of 10 million to 12 million euros could get a deal done. Nottingham Forest, Newcastle United, Tottenham and Fiorentina were all linked, and Fiorentina were reported to have offered around 12 million euros with a sell-on clause. Those were reports, not confirmed bids, so it's worth checking Sevilla's official squad list for his current status.
Salary and net worth: estimates only
Sevilla don't publish individual wages, and no official figure for Oso exists. The average first-team salary at the club is reported at around 2.2 million euros a year, and a young player recently promoted from the reserves will sit well below that. Icon Polls estimates his salary at 500,000 to 1 million euros per year.
On that basis, Icon Polls estimates Oso's net worth in 2026 at $1 million to $2 million, factoring in wages, bonuses and his commercial potential. A move to a richer league would change that quickly.
If watching a career like his gets you thinking about the players who went all the way, vote for the best football players of all time on Icon Polls.
Worth a Career Mode slot?
In EA Sports FC 26 he's a 72-rated left-back with 80 potential, 2-star skill moves, a 2-star weak foot and medium/medium work rates. Those numbers make him a sensible budget buy for anyone building a young La Liga side or hunting a fullback who will improve with regular minutes. He won't win you matches on day one, but he should grow into a dependable starter.
Loose ends
Has Oso played for Spain or Argentina?
As of August 2026 he had no senior international caps for either country, so both options remain open on paper.
Has he won any trophies?
Not yet at senior level. Most of his early career has been spent working his way into Sevilla's first team.
Why is he called Oso?
It's the nickname he has gone by throughout his career. Oso means "bear" in Spanish, though he hasn't made a public point of explaining where it came from.
