Tony Warner was angry. It was December 2008 and Warner, then third-choice goalkeeper at Hull, was doing some light training on his own before a Premier League match against Middlesbrough. It was an ordeal senior pros had to go through when not needed for duty and are usually given a wide berth.

A steward asked if he was playing. Warner responded with a mouthful. "'I said 'what the f---, do I look like I'm playing? I'm here at f-----g half 12,'" Warner told ESPN FC.

Warner stormed off to the changing room, face like thunder. The following Monday, management asked what was wrong and Warner explained his frustration. After hearing him out, they named him among the substitutes for their next match away to his former side Liverpool, a team for which he sat on the bench 120 times without making a first-team appearance. Warner thought he was back in the mix.

"The next game he [manager Phil Brown] drops me out again. So I go straight to Brown and say 'what the f---'s going on here, how come I've been dropped again?' He said 'Oh, we were at Anfield so as you started your career at Liverpool, I thought you would've liked to have been on the bench.'

"I said to him 'are you f-----g for real? Listen you, I know what Anfield looks like. I've been to Anfield more than f-----g anyone in this f-----g training ground. No one's been to Anfield more than I have. I know what it looks like inside, outside, upside down. I don't need a favour to see the club again'. [Brown] said 'OK, well that's what it is, you're out now'. So I called him all sorts of things, and then the door was slammed. That's it, it was like 'Warner's out' ... sometimes it just wasn't fair."

Brown, now manager at Swindon Town, laughed when asked about his tumultuous time with Warner.

"Third-choice goalkeepers are the hardest part of a Premier League outfit really," Brown told ESPN FC. "Where Tony was concerned, he was a challenge as he had a real strong belief in his own ability. But the bottom line is, that big character counts for nothing if you're not making saves, or keeping clean sheets."

Tony Warner symbolises the frustrating life of a third-choice keeper: warming the bench and serving as cannon fodder during training. Getty

Welcome to the life of the third-choice goalkeeper, football's version of the perpetual understudy. You are at every training session, standing in as the hapless target as strikers try to impress the coach by firing rockets at goal. On matchday, you train and travel with the team, knowing that unless the extremely unexpected happens (both the first-and second-choice keepers pull out) you'll be watching from the stands, or at best, the bench. The next week? Maybe a reserve game, otherwise the same routine, again.

In a summer where Premier League clubs spent in the region of £209 million on goalkeepers, including two world-record transfer fees for Alisson (£66.8 million) at Liverpool and Kepa (£71.6m) at Chelsea, there was intrigue around two moves which cost a collective £1.5m this summer. Robert Green, 38, and Lee Grant, 35, joined Chelsea and Manchester United, respectively. Both will likely be included in their Premier League and Champions League squads, but, for some rotten fortune, neither will see action this season: Kepa and Willy Caballero are ahead of Green and Grant has David De Gea and Sergio Romero in front of him. So they are the old, safe pairs of hands; the custodians for training sessions. Of course, it's not charity work: third-place keepers can earn a decent wage -- reports suggest Green and Grant are on £20k per week.

There are three types of third-choice goalkeepers. The first: the fresh-faced, un-bruised goalkeeper at the start of his career, like Lenny Pidgeley at Chelsea in 2004. He was behind Petr Cech and Carlo Cudicini, but happy to be at his boyhood club.

Second, there's the frustrated senior pro kicking his heels who has fallen down the pecking order and will likely seek a move, like Warner at Hull.

Finally, you've got the veteran goalkeeper in the twilight of his career being paid a handsome package to impart wisdom to young goalkeepers while being the break-glass-and-press-here SOS option, like Green and Grant.

Harry Redknapp managed Green at Queen's Park Rangers from 2012 to 2015 and is thrilled his old goalkeeper has this opportunity at Chelsea, but also knows full well the struggles of keeping a third-choice keeper happy.

"Sometimes the lads are pleased to come to a good club and you take them everywhere with you. I had someone like Jimmy Walker at Spurs who did that for me," Redknapp tells ESPN FC. "It's a great move for Rob Green. Rob's been a top goalie, but he might have been struggling for a club and now he's back in there, training every day and he's part of the Chelsea set-up.

"Goalkeepers are a special breed," Redknapp continued. "They come in and work their socks off. Green and Grant are cracking professionals, as I had with Jimmy and Carlo. And in the end, sometimes they're teaching the first-team keepers a thing or two. If Rob Green was ever needed, he wouldn't let you down, he'd do a job and you'd have confidence in him."

Mark Schwarzer experienced all three roles in the goalkeeping ladder in his 26-year career. He played 539 first-team games for Middlesbrough and then Fulham, finished his career with two seasons at Chelsea and one at Leicester in the Green and Grant role. Over the course of those final three campaigns, he made 10 Premier League appearances and was part of two title-winning squads.

"It's harder when you're younger and you have aspirations to be playing all the time," Schwarzer told ESPN FC. "If you're younger, you're soaking up the atmosphere, trying to process it all, but you're basically there just to get shot at.

"At the end, like when I was at Chelsea, you accept that you are a training goalkeeper and you have to take that on board," Schwarzer added. "It can be demoralising, as you are cannon fodder. It doesn't matter how hard you work, or how often you are working, you know you're the one to be shot at in training ... It can be tough to take."

Schwarzer feels it will be easier for Green to adjust to life at Chelsea than it will be for Grant at Manchester United only because Green played the third-choice role at his former club Huddersfield while Grant had more first-team action for Stoke City last season.

Not all third-choice keepers are miserable. Just ask Mark Schwarzer, who was behind Petr Cech and Thibaut Courtois in the pecking order. Getty

"For me at Chelsea it was great, as Jose [Mourinho] was appreciative and understood that [third-choice] position was tough, but also important as it's about being positive and doing the right things ... [because if you acted] disappointed it would have an effect on the rest of the players," Schwarzer said. "They want you to be at your peak to ensure the guys you are training with are getting the most of it."

While Schwarzer was at the end of his career, Pidgeley began his goalkeeping journey at Chelsea. Now at Farnborough Town, combining duties with managing his late father's landscaping business, he looks fondly back on his three seasons at Chelsea where he made two first-team appearances.

"It's all about timing, really," Pidgeley told ESPN FC. "I was 20, 21, then, and to be at a big club, I wasn't really expecting to play, and I was happy. It wasn't stressful, and I wasn't getting upset. But I was on the bench sometimes and when you're sat there at White Hart Lane, aged 20 or whatever, in that hostile an environment, with so much at stake you're thinking [about the other keepers], 'please don't get injured, I don't want to get on.' It's full on, putting your neck on the line."

But Pidgeley learned from those early struggles to become first-choice at Millwall for two years before heading off on a nomadic existence during which he played for another 11 clubs en route to his current spell with Farnborough. With age came frustration.

"I was at Carlisle, Bradford, Exeter and I was on the bench or stands, and I was like 'What am I doing?'" he said. "I felt in my mind I should have been playing and I was a long way from home, and if you're not playing when you think you should be, then you get frustrated. It gets to the point where you just can't take it much longer, but it all depends on the club and the personnel."

He never descended into a rant quite like Warner's, but can sympathise after hearing the tale of Warner's altercation with Brown. "Yeah, that sounds like Denzel," Pidgeley said, referring to Warner's nickname from the character in BBC sitcom "Only Fools and Horses."

"I was third-choice at Cardiff and fell out with the management, I ended up in the stands," Warner said. "There are different types of goalkeepers -- you have your number one, which is great. Then you have others who are really happy to be on the bench and they just stay there and you'll probably get another contract as you're not kicking the door down and you're a safe option.

"I'm not like that, I can't be like that, and it's not in my makeup. Rightly or wrongly, I knock on doors, and sometimes your frustration overspills ... I've knocked on the doors and said to managers, 'How the f--- is he ahead of me?' and then I'll say one or two words, doors get slammed, and that's that then. The manager won't put you on as then he'll think it's your idea, so he'll f--- you off another way."

Brown sees third-choice keepers as being essential to a squad. But there are only so many run ins he could manage. "That's management," Brown said. "You don't tell lies; you don't lead anyone up the garden path. When you're selecting the team, you're selecting the best you have.

"Goalkeepers are a department within themselves, really. Tony was a challenge, but a good challenge."

Warner is now at Accrington Stanley as goalkeeping coach and even sat on the bench for their first game of this season, aged 44, as they were without a back-up option.

As the kettle boils, he talks of why he can understand why Green and Grant made the moves they did. It's not an acceptance of defeat in joining as third-choice, but more an opportunity to add an unexpected chapter to a career that's at risk for falling into a nomadic denouement, full of short-term moves.

"When their careers are finished, they have played for the most successful clubs in English football," Warner said. "They'll both get a nice pay-day out of it, so it's bonus, bonus, bonus for them."