Casillas, 32, made his debut for Los Blancos in 1999, but has fallen out of favour at the club since January's arrival of fellow Spaniard Diego Lopez. Casillas has missed part of last season with a hand injury.
The Spain captain is reported by Yorke to have said:
If the situation doesn't change within three months and you ask me the same question, I'd probably say that I'll be looking to leave.
In September I wanted to leave and I was going to tell the president that I wanted to go, but I decided to be a part of this squad and this club for a lot longer. I always wanted to stay at Real Madrid but I'd like to play and compete more.
Casillas has long been regarded as one of Europe's best goalkeepers, with two Champions League winner's medals, five league titles and a raft of international cups to his name. His current lack of playing time—just 105 minutes this season—is not enough for a keeper of his quality.
More importantly for the Real Madrid man, his World Cup place is on the line—at least as a starter.
There has been little argument over the Spain No. 1 jersey in the last decade, but there are plenty of contenders to take his starting berth should he arrive at the competition next summer with few games under his belt—Barcelona's Victor Valdes being the prime contender.
With regards to possible destinations, Arsenal and Manchester City have this season been frequently touted as possibilities—as reported in this Talksport article.
Of the duo, it is the North London side who would have to be considered more likely, with City unlikely to sideline Joe Hart just yet—despite a string of high-profile errors.
Arsenal's faith in Polish keeper Wojciech Szczesny remains strong, but he was dropped for a period of last season by Arsene Wenger, who could arguably benefit from a more experienced head between the posts.
There are very few sides in world football for whom Casillas wouldn't be a valuable addition. He is a tremendous shot-stopper, an outstanding all-round keeper and brings a wealth of experience that few can rival.
Add in the fact he should still have another five or six years at the top level of the game, and it is clear that he could be a top signing—should Madrid authorise his departure.
A leaked footage from Spanish TV Cuatro revealed Reina suggesting explicitly to Casillas to leave Real Madrid— Tancredi Palmeri (@tancredipalmeri) October 14, 2013
Selling Casillas would be a bold move from the club, given that he is one of just a few academy products to feature in the first team. If he is not going to regain his first-team place, though, it would be disrespectful to deny him a move on those grounds.
Decision time is approaching for both Casillas and Real Madrid, with a host of clubs no doubt aiming to profit if the pair decide to part company.