Journalist Matteo Moretto first reported both targets, with sporting director Antonio Cordón confirmed to have sounded out the pair as part of early planning for next season.
Joselu Mato, 36, will leave Qatari club Al-Gharafa at the end of his contract in June 2026 and has decided against a renewal, making him available for nothing.
The former Real Madrid striker, who scored the winner that helped secure the club's fifteenth European Cup in Lisbon in 2024, scored 27 goals across two seasons in Qatar.
Diego Conde, 27, has barely featured for Villarreal since the arrival of Luiz Júnior, falling to third in the goalkeeping pecking order despite winning the Zamora Trophy for best goalkeeper in the Spanish second division as recently as 2024.
He is contracted at Villarreal until 2029 but the club are open to allowing him to leave, potentially on loan with an option to buy.
Head coach Luis García Plaza is currently focused on keeping Sevilla in the top flight, and Cordón has been clear that both deals depend entirely on survival. The club sit in the relegation zone with five games remaining.