​Porto goalkeeper Iker Casillas is thought to have retired from football after suffering a heart attack in early May.

The former Real Madrid shot stopper was rushed to hospital during a training session, and was confirmed to have suffered a heart attack. Fortunately, he recovered and was ​discharged from hospital just a few days later.

However, according to ​The Sun, the health scare has left Casillas considering his future, and he has ultimately decided to retire at the age of 37.

Widely regarded as one of the finest goalkeepers in history, Casillas made his name with ​Real, rising up through the youth ranks before making his first-team debut in September 1999 at the age of just 18.

He soon became Los Blancos' first-choice goalkeeper, and he went on to make 725 appearances, winning five ​La Liga titles and lifting the ​Champions League on three different occasions. He sits second on the list of all-time appearances for Real, behind only legendary striker Raul, who managed 741 outings for the club.

Iker Casillas

After losing his place at the Santiago Bernabeu, Casillas opted to join Porto in the summer of 2015, where he was able to continue playing regular first-team football. He made 156 appearances for the Portuguese side, before suffering the heart attack on 1 May.

On the international stage, he was equally as successful. The Spaniard made his debut in the summer of 2000, and went on to make a record 167 appearances for his country, winning the European Championships in both 2008 and 2012, as well as the World Cup in 2010.