The young stopper was sold by TFC after Tobido had originally agreed pre-contract terms.
While accepting the sale made good business sense, Casanova also told Mundo Deportivo: "Barça has made a future signing. In these four months, Barça will measure what level he has, if he can make the first team or if he must be loaned.
"I'm a little annoyed, a little angry because it did not sit well for me to leave, to leave us like that. I was one of those who bet a lot on him. I put him in Ligue 1, I've believed a lot in him ... When a player is free he can choose and leave.
"I'm a bit upset, bitter, but top football is like that."