It's always a dramatic and bizarre moment when an outfield player goes in goal.
First comes the panic, as fans start to wonder who will take one for the team. The chosen one then chucks on a spare goalkeeper shirt - which is usually far too big - and slides their hands into some sweaty gloves before facing the daunting prospect of making saves.
Several outfield players have experienced this during their careers - such as Kyle Walker, Harry Kane, John O'Shea, Rio Ferdinand, Phil Jagielka and John Terry. The latter famously donned the gloves in a Premier League game in 2006 - but it's not a happy memory.
That day, Terry's Chelsea travelled to Reading in pursuit of three precious points in the title race. The Blues were expected to beat the newly-promoted side, as they had recently won back-to-back Premier League titles under legendary manager Jose Mourinho.
Terry started the game at the heart of Chelsea's defence with Petr Cech - one of the best goalkeepers in Europe - standing behind him. The stopper missed just seven Premier League games during the previous two seasons, such was his importance to the team.
Cech's injury
Disaster struck in the first minute, when Reading goalkeeper Marcus Hahnemann hit a long ball forward. It bounced over Chelsea's defence and into the path of forward Stephen Hunt, who sprinted desperately to get to the ball ahead of an onrushing Cech.
Do you remember when John Terry went in goal? Let us know in the comments below!
The goalkeeper won the challenge, but the momentum of both players led to a sickening collision involving Hunt's knee and Cech's head. The latter stayed on the ground and needed to be stretched off. It was later confirmed Cech had suffered a fractured skull.
At that point, Cech's career - and life - hung in the balance. Thankfully, he recovered after surgery and went on to play more than 900 professional games for club and country - winning four Premier League titles, the Champions League and several other honours.
Cech wore a rugby-style skullcap for the rest of the career, becoming a trademark. Recalling the incident years later, he told Sky Sports: "Things could have been different, the doctors tried not to scare me too much and I never asked too much.
"But if you ask my wife, even now, she does not look too well. For her, the experience was a thousand times worse than it was for me. It was a very close call. I had a depressed skull fracture. A few pieces of bone went in quite deep, that was the biggest danger."
Cudicini's injury
Cech's replacement in the Reading game was Carlo Cudicini, his long-term understudy who spent nearly a decade on Chelsea's books. An own-goal gave the Mourinho's side a 1-0 lead before another nightmare scenario unfolded in the last few seconds of the game.
As Reading chased a late equaliser, defender Ibrahima Sonko clattered into Cudicini after the goalkeeper bravely punched a corner away from danger. The incident left Cudicini lying on the ground while the game continued, almost resulting in a Reading goal.
Referee Mike Riley then stopped play after noticing Cudicini was unconscious. The goalkeeper needed to be stretched off wearing a neck brace and the injury dominated the headlines just as much as Cech's - if not more - such was the severity of it.
Cudicini's injury was ultimately not as serious as Cech's, although it still kept him out of action for three Premier League games. He later recalled: "I lost consciousness almost immediately and I woke up in the ambulance on the way to the hospital.
"The first image I had was a really scary one because I had the face of our doctor right in front of me and they weren't exactly a good looking doctor, so I was a bit shocked!
"Then I realised where I was, and the doctor explained to me what had happened, and after that initial shock, I have to say that I was fine - it was just a matter of going through some tests, sleeping in the hospital and then I went back home to recover."
Terry gets the nod
Hilario, Chelsea's third-choice goalkeeper, was selected for Chelsea's next three Premier League fixtures - yet he wasn't on the bench against Reading. Back in 2006, managers were allowed to make just three substitutions each game, with five players on the bench.
So, if the substitute goalkeeper got injured - or the manager had already made three changes - an outfield player had to go in goal. Taking one for the team against Reading was Terry, Chelsea's captain and one of Mourinho's most-trusted lieutenants.
Thankfully for the Blues, Terry wasn't required to much goalkeeping. His main act was teasing Reading striker Kevin Doyle to close him down before picking up the ball and booting it up field. Riley soon blew his full-time whistle, leaving Terry a relieved man.
Terry hasn't spoken much about the game since it happened and his thoughts were obviously with Cech and Cudicini after the game. "We are very concerned," he told reporters. "They both got knocked out and are fully concussed, but we hope they are okay."
Terry went on to retire from playing in 2018 with 15 major honours to his name, including five Premier League titles. A banner at Stamford Bridge reads: "JT CAPTAIN, LEADER, LEGEND". Should Chelsea fans add "GOALKEEPER" to that? Probably not.
