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: