"Sergio Ramos has informed Sevilla FC that he will not stay next season," the club said in a statement.
Antoine Griezmann struck a hat-trick in a 3-0 win over 10-man Celta Vigo to help Atletico Madrid climb provisionally second, in hot pursuit of their city rivals.
Sergio Ramos has not played against Real Madrid since 2005 but on Saturday, his Sevilla team welcome the Spanish league leaders to the Sanchez-Pizjuan for a reunion.
Real Madrid legend Sergio Ramos's own goal handed his old enemy Barcelona a narrow 1-0 win over Sevilla on Friday in La Liga, taking the Catalans top of the table.
Sergio Ramos made his second Sevilla debut in a narrow win over Las Palmas, while Mason Greenwood played his first match for Getafe, on loan from Manchester United
Castro had been sceptical last month when it was reported that Ramos was keen to return to his boyhood club.
Veteran former Spain defender Sergio Ramos said Monday he was returning to his home-town club Sevilla after 18 years away.
Sergio Ramos, Jordi Alba, Sergio Busquets, N'Golo Kante, Angel Di Maria and Roberto Firmino are also among the seasoned World Cup and Champions League winners being lined up for the Saudi Pro League, the source said.
Spanish defender Sergio Ramos is leaving French Champions Paris St Germain, the Ligue 1 club said on Friday.
Real Madrid moved top of La Liga as Karim Benzema struck in each half to earn the visitors a 2-1 win over Athletic Bilbao at San Mames on Wednesday.
Cristiano Ronaldo can move ahead of Raul as Real Madrid's top goalscorer of all time as Los Blancos take on Athletic Bilbao.