Real Madrid are aiming to bring Lyon striker Mariano back into the fold, rather than cashing in on the sell-on percentage added to the deal that took him to France last summer.
"Madrid had a buy-back option and they have told us that they are going to exercise it," Castro said, per Brooke.
"But the player hasn't told us anything yet and we are waiting for him to respond because he's said a thousand times that he wants to play for Sevilla," Castro added.
As reported by Marca's S. Siguero and A. Fernandez, Sevilla have offered €30 million to Lyon, but the club previously hoped to make more than double that in a sale to a Premier League side.
If Lyon had sold to Sevilla, the sell-on clause would net Real €12 million, per the report.
The 25-year-old spent the last few years playing at various levels for Real and its youth teams and finally got the chance to impress at the top level last summer with his move to Lyon. He made the most of his opportunity, bagging 18 goals in Ligue 1.
Here is a look at those goals:
Despite that great scoring form, there was little chatter surrounding the Dominican this summer. Most of the attention at the Groupama Stadium was centred on Nabil Fekir, but Lyon's other top forwards―including Memphis Depay―largely flew under the radar.
Sevilla's interest should come as no surprise, as the Andalusians have quite the reputation for spotting bargains and value in the open market. Just this summer, they've already added the likes of Aleix Vidal, Tomas Vaclik, Andre Silva and Maxime Gonalons.
This offer has also come to light after the Premier League transfer window closed, limiting the competition for Mariano's services.
But for Real, there might be more value in a return, rather than the 35 per cent sell-on clause.
Los Blancos haven't yet invested in a top striker to replace Cristiano Ronaldo, and entering the new campaign their options are Karim Benzema, Borja Mayoral and Vinicius Junior. While Benzema is solid, Mayoral has yet to break through, and the inexperienced Vinicius will need time to settle at the club.
Mariano already knows the club and should have no issues settling in. This late in the summer, he could be the perfect value buy, and his arrival could allow Vinicius or Mayoral to go on loan to gain some much-needed experience.