Some players stick around too long. Some are gone too soon. Sometimes, there's a list with a little of both. Nevertheless, on that note, here's a look at the five players who were forced to retire due to health conditions:

5 Pierluigi Casiraghi

Time at Monza, Juventus and Lazio preceeded Casiraghi’s eventual career-ending move to Chelsea, where he made just 10 appearances before colliding with West Ham goalkeeper Shaka Hislop.

Four years and 10 operations later, the Italian eventually retired in 2002, meaning he played his last game aged just 28.

4 Luc Nilis

As a former strike partner of both Ronaldo and Ruud van Nistelrooy at PSV Eindhoven, Aston Villa fans placed plenty on the Belgian's shoulders when he arrived at the club in 2000. started well, too, as he scored on his debut against Czech side Dukla Pribram in the Intertoto Cup before finding the net in his first Premier League outing against Chelsea.

Sadly, though, his career came to a shuddering end during just his third league game for his new club at Ipswich Town. Nilis collided with Tractor Boys goalkeeper Richard Wright as he chased a ball into the area, suffering a double compound fracture of his right shin which at one point threatened to lead to his leg being amputated. Thankfully that was avoided, although the injury proved to be the end of the Belgian's career.

3 Just Fontaine

A prolific striker in his day, Just Fontaine set the record for most goals in a single World Cup campaign when he scored 13 goals for France in 1958 – a record he holds to this day and likely always will.

Fontaine, who scored 30 goals in just 21 caps for the French national team, formed part of the highly successful Stade de Reims team that won three league titles and reached the final of the European Cup in 1959. Sadly for Fontaine, he had to retire at the age of 28 due to injury, just four years after his exploits at the World Cup in Sweden.

2 Ruben de la Red

Ruben de La Red was quite the majestic midfielder in the 2000s and his dazzling performances for Getafe after graduating from the Real Madrid academy caught the attention of many fans and critics alike. de la Red was absolutely stunning in midfield, with his ability to control a game and stunning skill in passing and creating chances was lauded by many. But after returning to Real Madrid in 2008, a serious heart condition turned his career upside down. De la Red even fainted during a match for Madrid and his weak heart couldn't handle the pressure of the games. That condition resulted in him having to voluntarily retire at the age of 25, with a really promising career coming to a bitter end.

1 Fabrice Muamba

Muamba was a promising passionate midfield player for The Bolton Wanderers and made over 100 appearances in his five-year career with them. Sadly, he collapsed on the field during an FA Cup match between Bolton and Tottenham Hotspur due to a cardiac arrest. Although he made a full recovery, doctors advised him to stop playing because of his weak heart.