Last week the former Chelsea manager gave the strongest indication yet that he wanted to return to the Premier League at the end of the season by saying: "I want to be where I am loved. In England I am loved by the press, the fans, I am loved by some clubs, especially one."
The 50-year-old followed that up with a confrontational press conference in which he criticised Casillas, hinting that, in his opinion, the goalkeeper "thinks he is above the rest" of the squad.
He also remarked that his biggest regret in his three years at the Bernabeu was not signing Diego Lopez, who is now his first-choice goalkeeper, at the end of his first season in charge.
Those comments heightened speculation over his future and seemed to be a further indication that he was on his way out.
However, in a press conference ahead of Wednesday's Primera Division clash with Malaga, the Portuguese was again coy on his future - and even suggested he has not ruled out remaining in the Spanish capital.
He said: "I have considered staying on."
Reports in Spain had accused Mourinho of involving himself in public spats with key players in a bid to force the board to sack him and hand him a pay-off.
However, he denied those claims, saying: "I will only earn money until the last day I work here. I don't want a single euro more."
Mourinho's criticism of Casillas led to centre-back Pepe speaking out against the coach after Madrid's 4-3 win over Real Valladolid at the Bernabeu on Saturday.
"The boss' comments weren't appropriate. Iker is a legend, both at this club and in Spain, and he deserves more respect," the defender said.
Mourinho's response today was to accuse his fellow countryman of sour grapes after losing his place in the side to 19-year-old Raphael Varane.
"It's very easy to analyse what Pepe said. His problem has a name - it is Raphael Varane," the coach said.
"We are talking about frustration. It's never easy for a 31-year-old to be rolled over by a boy of 19 years of age.
"I had the courage to play him (Varane), because I believe that he is the future of Real Madrid, along with Sergio Ramos. The problem is very simple - Pepe's life has changed."
He also defended his decision to make Lopez his number one ahead of Casillas.
"I like Diego Lopez more as a goalkeeper than Casillas. It's simple - it's not a personal decision. I like a goalkeeper who can play well with his feet, who is good in the air and who is a phenomenon between the posts.
"I like a different profile of goalkeeper, in the same way that Casillas might say he prefers a coach in the style of (Spain coach Vicente) Del Bosque.
"While I am the coach of Real Madrid, Diego Lopez will play, in normal circumstances. It's simple.
"I accept that people may say I know nothing about football because of that decision, but I say respect a coach who decides to play Diego Lopez. I'm the coach. It is my decision."
Mourinho admitted that this season "could have been better", with the capital club on the verge of relinquishing the title to arch rivals Barcelona, but said he wants Madrid to finish second - an objective they will be closer to achieving if they beat Malaga tomorrow.
"We want to finish second," he said. "Second is not enough but it's the only target we can have. We still need some points and we have to try and win the match to finish second as soon as we can.
"On the other side we have a very good team that is coming to create us problems, like they always do. They are a good defensive team that play well on the counter-attack. If you do not play them seriously or in the best possible way, it's possible to lose."
Former Madrid boss Manuel Pellegrini does not think the uncertainty surrounding Mourinho's future will make it any easier for his side.
"There are always internal problems that affect teams, that can happen to Madrid or to us. But it's wrong to think we can win because the other team has problems," he told reporters.
If Madrid fail to win, Barcelona will become Primera Division champions, but Pellegrini, who was sacked by Madrid after just a year in charge and succeeded by Mourinho, said that revenge was not on his mind.
"We want to get points regardless of what other people say. We want to keep gaining points and climbing the table.
"I want my team to play like a great team. We have a system and philosophy of how to play. Madrid won't go out to play thinking about their problems, they'll be thinking about the responsibility they have for their club."