That's according to Football Insider, who suggest that the Whites are eager to get the former Real Madrid man off the books to free up space on their wage bill.
The report states that Casilla is on around £40,000-a-week, and that Leeds are aware that they will struggle to engineer a deal for him at that price.
As such, they could look to cut their losses and let him leave Elland Road for nothing, with view to bringing in another stopper to act as Illan Meslier’s understudy.
The young Frenchman has cemented his spot as first choice between the sticks in Yorkshire, and has featured in all but one of Leeds' Premier League matches so far this season.
Casilla has managed just three outings in all competitions this term, conceding five goals in the process from an xCG (expected goals conceded) of 4.71.
Elsewhere, Bradford City manager Mark Trueman has opened the door for Leeds youngster Bryce Hosannah to return to the club on loan this summer.
The 21-year-old has spent time with the Bantams before, but had his previous spell cut short by injury.
Speaking to the Telegraph & Argus, Trueman said: “We want to bring the best players possible to the club, whether that’s loans or signings in the summer window.
“If Bryce is a player that is available, there is always potential that he could return.”
We’ve gathered the rest of today’s Premier League transfer rumours below:
. LEEDS, ENGLAND - DECEMBER 27: General view inside the stadium prior to the Premier League match between Leeds United and Burnley at Elland Road on December 27, 2020 in Leeds, England. The match will be played without fans, behind closed doors as a Covid-19 precaution. (Photo by Nigel French - Pool/Getty Images)
Elland Road. (Photo by Nigel French - Pool/Getty Images) Photo: Pool
. Tau unhappy at Brighton
Brighton forward Percy Tau is unhappy in England and ‘cannot continue in the Premier League’. The South Africa international will ‘change clubs’ in the next market. (Voetbal24) (Photo by Peter Powell - Pool/Getty Images) Photo: Pool
1. Tau unhappy at Brighton
Brighton forward Percy Tau is unhappy in England and ‘cannot continue in the Premier League’. The South Africa international will ‘change clubs’ in the next market. (Voetbal24) (Photo by Peter Powell - Pool/Getty Images) Photo: Pool
2. Albion want Mingueza
Brighton, Real Betis and Sampdoria have expressed their interest in Barcelona defender Oscar Mingueza. (Mundo Deportivo) (Photo by LLUIS GENE/AFP via Getty Images) Photo: LLUIS GENE
3. Toffees plot Koulibaly raid
Everton are confident that it will take way less than £89 million to prise Kalidou Koulibaly from Napoli this summer. (Football Insider) (Photo by Marco Luzzani/Getty Images) Photo: Marco Luzzani
4. Cavani taking pay cut
Edinson Cavani is willing to take a huge pay cut to join Boca Juniors from Man United this summer. (Football Insider) (Photo by Michael Regan/Getty Images) Photo: Michael Regan