The goalkeeper was left out of Marcelo Bielsa’s squad for the 2-0 defeat at West Ham United in favour of Elia Caprile.
Casilla’s cryptic post, in Spanish, translated as: “I’m slow to go, because I believe in changes. And I wait, and I endure, and I keep. But one day I get tired, and without saying anything I leave everything and go.
"Believe me that once I get tired I won’t come back again, because I give everything before I leave.”
Given his exclusion on Monday, it was presumed the 34-year-old was referring to his Elland Road future, however he has provided clarity.
Responding to a post from LUFCFANZONE, which carried quotes from Casilla’s agent, the former Real Madrid ace insisted it was about personal matters and not at all related to Leeds.
He said: “Honestly, there are people with very boring lives. I have not said anything bad about the club or my situation.
"They are personal things, nothing to do with Leeds. #mot”.
Coincidentally, Leeds have been linked with a move for Alaves keeper Fernando Pacheco by Spanish outlet GOL Digital.
It is claimed the Whites view the 28-year-old as a potential replacement for Casilla, should he end up leaving this summer.
However, Southampton are also tracking Pacheco and are willing to pay £8million for his services, a figure Leeds “would also negotiate”.
The two clubs’ chances of landing Pacheco, also a former product of Real Madrid’s academy, could increase if 19th place Alaves are relegated from La Liga.
Here are the latest transfer headlines from around the Premier League, including much more Leeds:
1. Werner could leave Chelsea
Chelsea striker Timo Werner may quit the club in the summer, just one year after his £45million move from RB Leipzig. There is a growing expectation that the German will return to his homeland “in the next year or two”. (Football Insider) Photo: Laurence Griffiths
2. Barca offer Aguero contract
Barcelona have offered a contract to Manchester City striker Sergio Aguero, who is out of contract at the Etihad Stadium this summer. (Tycsports) Photo: Gareth Copley
3. Cavani will decide future in May
Manchester United striker Edinson Cavani will wait until the end of the season before deciding his future, despite the Uruguayan's father indicating he wanted to sign for boyhood club Boca Juniors. (ESPN) Photo: NAOMI BAKER
4. Brighton interested in Eder
Portuguese striker Eder is set to leave Lokomotiv Moscow at the end of his contract in June, with Brighton and Hove Albion expressing an interest in the 33-year-old. (A Bola) Photo: GABRIEL BOUYS
5. Newcastle win Bondswell race
Newcastle United have beaten Leeds United and West Ham to the signing of 18-year-old free agent Matthew Bondswell following the left-back's release from Bundesliga outfit RB Leipzig. (Daily Telegraph) Photo: Laurence Griffiths
6. Hendry attracting tons of interest
KV Oostende could sign Jack Hendry from Celtic for around £2million then offload him in the same summer for £10m. Aston Villa, Brighton and Wolves are keen, while Leicester, West Ham, Crystal Palace and Newcastle have kept tabs on his progress. (90min) Photo: VIRGINIE LEFOUR