Gustavo Rubén Caballero González (born 21 September 2001) is a Paraguayan professional footballer who plays for club Portsmouth, on loan from Campeonato Brasileiro Série A club Santos, and the Paraguay national team. Mainly a winger, he can also play as a forward.
He began his career in his country's APF División de Honor, playing 116 games and scoring 19 goals for Deportivo Capiatá, Sportivo Ameliano, and Nacional Asunción. After finishing as joint top scorer of the Apertura in 2025, he transferred to Santos, who then loaned him to Portsmouth.
Caballero represented the Paraguay under-23 team at the 2024 Olympic tournament.
A Deportivo Capiatá youth graduate, Caballero signed his first professional contract on 1 July 2019. He made his debut in the Paraguayan Primera División on 12 July, starting for in a 1âÂÂ0 home win over Sportivo Luqueño.
Caballero featured in seven league matches for Capiatá during the 2019 season, as the club suffered relegation, and also helped the side to reach the semifinals of the 2019 Copa Paraguay.
After the 2020 season was cancelled due to the COVID-19 pandemic, Caballero also spent the 2021 campaign unemployed before going on a trial at Sportivo Ameliano in January 2022; initially a member of the reserve team, he impressed during the pre-season and earned himself a first team spot. He scored his first professional goal on 20 March 2022, netting the opener in a 2âÂÂ0 away win over Olimpia.
Caballero contributed with two goals and two assists in 12 matches for Ameliano during the 2022 Apertura tournament.
In July 2022, Caballero joined Nacional Asunción, who had been in irregular form and mid-table positions in the first half of the season. In his second match for La Academia on 25 July, he scored his first goal in a 2âÂÂ1 win at 12 de Octubre.
On 28 February 2023, Caballero scored his first continental goal in the Copa Libertadores, albeit in a 5âÂÂ1 loss away to Sporting Cristal of Peru, eliminating his side 5âÂÂ3 on aggregate; he was soon afterwards demoted to the reserve team as a punishment for alleged tactical disobedience.
In July 2023, Caballero returned to Ameliano for the second half of the season. He only managed to make eight appearances for the side, with only three starts.
Back to Nacional for the 2024 campaign, Caballero soon established himself as a starter. On 5 September of that year, he scored a hat-trick in a 5âÂÂ0 Copa Paraguay away routing of Cristóbal Colón de Juan Augusto SaldÃÂvar. His performances attracted the interest of Olimpia, but nothing came of it.
Caballero was the top scorer of the 2025 Apertura tournament with nine goals (along with Juan Iturbe), which led to a move to Libertad on 7 July of that year. Five days later, however, the deal collapsed amidst interest from foreign clubs.
In July 2025, Campeonato Brasileiro Série A side Vasco da Gama made an offer to obtain Caballero on loan for US$400,000 with an option to purchase for US$2.2 million. On 24 July however, Santos of the same league announced his signing on a four-year contract, paying US$1.6 million for 50% of his economic rights.
Caballero made his debut for Peixe on 26 July 2025, being deployed as a right wing-back in a 2âÂÂ2 away draw against Sport Recife. He scored his first goal for the club on 10 August, netting the winner in a 2âÂÂ1 away success over Cruzeiro; he also provided the assist to Guilherme's equalizer.
On 2 February 2026, the last day of the transfer window, Caballero was loaned to EFL Championship club Portsmouth for the rest of the season. Manager John Mousinho said that he had been tracking him since the previous year.
On 21 February 2026, Caballero scored his first goal for the club in a 3âÂÂ1 victory over Millwall at The Den.
Caballero made his debut for the Paraguay national under-23 team on 8 June 2024, as a substitute in a 4âÂÂ0 friendly loss to neighbours Argentina. He was named in the squad for the 2024 Olympic event in France, but was moved to standby after veteran Fabián Balbuena received late permission from Dynamo Moscow.
Caballero was restored to the main team days later when Fabrizio Peralta was denied permission by his Brazilian club Cruzeiro, and then dropped again as Julio Enciso was allowed to play by Brighton & Hove Albion. On the day before the tournament, he was finally reinstalled in the squad when Diego González suffered an injury. He played in all three matches in the group stage, but was an unused substitute in Paraguay's quarterfinal loss to Egypt.