Agustín Sienra, a 26-year-old Argentine central defender, has agreed to a one-year contract with Castellón. He is transferring from Defensa y Justicia and is set to make his debut in Spanish football under the guidance of coach Johan Plat. Sienra, who is also capable of playing as a left-back, was nurtured in Defensa y Justicia's youth academy. He progressed to their first team in the 2020-2021 season and had loan spells at Villa San Carlos and San Martin San Juan in Argentina's second division. In the previous season, he made his debut in Argentina's top division, appearing in two matches during the Torneo Apertura with Defensa y Justicia. Sienra's signing is Castellón's ninth of the season, addressing a crucial defensive gap left by Juan Escobar's departure. His ability to play in both central and left-back roles is anticipated to be a significant asset for the team, which currently has three central defenders and is contemplating an additional signing before the transfer window closes.