Portsmouth secured Gustavo Caballero from Santos on deadline day of the winter window, with the deal structured to give the Championship club an option for a permanent transfer. Portsmouth have taken the 24-year-old Paraguayan winger on loan until June 2026. The agreement already generates income for Santos, with the Brazilian club set to receive around £850,000 (€1m) from the operation. Portsmouth can buy Caballero’s rights if he reaches a defined target during his time in England; that target is tied directly to appearances in the Championship, a condition described in Brazil as realistic and likely to be met. If the clause is triggered, Portsmouth would pay around £4.25m (€5m) to secure 80% of the player’s economic rights. The remaining 20% would stay with Nacional, Caballero’s former club, which retains a sell-on percentage for any future transfer. Caballero only joined Santos in July 2025, arriving on a free transfer after leaving Nacional. He quickly was no longer part of the plans of head coach Juan Pablo Vojvoda. Portsmouth’s proposal arrived last week and negotiations proceeded quickly. Caballero, whose contract with Santos expires in December 2028, has a current market value of €1.00m. This season, he has made one appearance in Série A and one in the Campeonato Paulista.