Wolverhampton Wanderers are reportedly prepared to match their club-record transfer fee of £18m in order to secure the services of Jonny Castro on a permanent deal.
The 24-year-old moved to Molineux on a season-long loan agreement from Atletico Madrid over the summer immediately after he had sealed a switch to the La Liga giants on a six-year deal.
The wing-back has been a key part of the Wolves side this term, appearing in 20 of their 24 league games to help them up to an impressive seventh place in the Premier League table.
According to the Express & Star, Wolves have moved quickly to try to make Jonny's move permanent and have initiated talks with Atletico, who are said to be "open" to agreeing a transfer before the window shuts tomorrow.
Jonny is thought to have signed for Atletico for a fee in the region of £6.3m last July but is now expected to be sold on for almost three times that amount in an £18m deal that would match the figure spent by Wolves on Adama Traore earlier this campaign.
The move for Jonny is expected to have a knock-on effect on the club's mooted permanent deal for Raul Jimenez, which could now be delayed until the end of the season due to Financial Fair Play (FFP) concerns.