Liverpool’s goalkeeping department has been an ever-changing landscape these past 18 months.
Since July 2018, the Reds have sold two, loaned three, broke a world record to land another before adding a couple more on free transfers.
They also gave senior debut to one in form of Caoimhin Kelleher last month, too.
A lot has changed since Loris Karius and Simon Mignolet fought it out for the status as first-choice keeper at Anfield last year.
Karius has been loaned to Besiktas, Danny Ward departed for Leicester, while Alisson Becker arrived with the short-lived tag as the world's most expensive goalkeeper. A year later Mignolet ended his six-year association with the Reds as Andy Longergan and Adrian joined as free agents around the same time Kamil Grabara left for Huddersfield on loan.
One man who has been at the heart of the goalkeeping revolution is coach John Achterberg, a man Jurgen Klopp endearingly describes as a "maniac".
"First of all, John is a goalkeeper maniac," Klopp told the ECHO last year. "He's working constantly.
"John is the first in the building and the last to leave. No matter how early I get into Melwood, I get up the stairs and he's already there - sat there with the laptop open watching goalkeepers from the other end of the world."
Klopp is not one to exaggerate where his goalkeeping coach is concerned. The former Tranmere Rovers man is devoted to his work at Melwood, often sifting through hours of footage and ending up knee-deep in thousands of subsequent reports as a result.
It enables him to stay at the cutting edge of goalkeeper trends and keeps his mind sharp when discussing the fortunes of glovesmen across world football. So, at a time when much is subject to change for Liverpool and their goalkeepers, what is a typical day like for the club's senior coach?
"I go into work and then I look at the goalkeepers out on loan, so I am looking at footage of Kamil and Loris," Achterberg tells the ECHO in an exclusive chat. "Obviously Loris is still our goalkeeper as well and then I am looking at the normal leagues who produce goalkeepers.
"You have to look at any you don't know, obviously you know most of them all already, but it if you don't, you take a look and see how they are moving. If one game is enough [to judge] then you leave it but if you think you need to catch more, that is how you have a look.
"I have about four of five thousand reports from some keepers you watch 10 or 15 times and then you stay on top of it. If you think they can be OK for us then you have to keep following them and you always have to prepare for a No.1, 2 or 3. And then in between you try to find keepers who are younger.
"You try to find out about 14, 15 or 16-year-olds. Do we need one? Can we bring them in? And that is obviously in combination with the Academy there. So I suggest them to them and they have a look. If they can bring them up and we have a look with Jack Robinson (goalkeeper coach) and we have a look too, to see if there is a possibility to bring them to the club.
"So you want to prepare for everything, always. You always look at who is out of contract, who has one year left, so that the transfer fee won't be too high and then obviously you have the best list ready for whatever needs to happen."
Achterberg's 10-year stint at Liverpool marks him out as the longest-serving member of the coaching staff at Melwood. From Karius’ Kiev nightmare and the £65m signing of Alisson, right the way through to Mignolet’s exit and Adrian’s Merseyside move, Achterberg has played a key role behind the scenes.
And while Klopp always has the final say on all things at Melwood, the Reds boss is on all things goalkeepers. So, just how big a role did he play in Liverpool smashing their £9m goalkeeper transfer record more than seven times over to land Alisson from Roma?
"I was convinced that if we are going to spend money then Alisson was the No.1 I would sign," he says. "Obviously what he has done up to now, it has worked out. You're looking around at the way we play and his movements and you have to say he is the No.1.
"Looking at Premier League level, he has worked out this move himself with the qualities he has shown over the years. Obviously these moves need to come off, because you look at David de Gea (at Manchester United), it took one or two years before he was at his level and had the trust.
"He only came back into the Manchester United side because the other goalkeeper got injured.
"So you don't have a lot of time to settle because the talking is there all the time and I think Ali and the boss have changed the way the crowd are really with the way they manage and play. Now the crowd is positive from the first second and are not worried if the ball is in the air or the box."
The blockbuster deal for Alisson was a high-risk strategy for Liverpool in the summer of 2018. Signing a shot-stopper for £65m was out of character for a club whose £9m deal for Simon Mignolet in 2013 stood as their record purchase for a No.1 previously.
After goalkeeping errors cost Liverpool so dearly in the Champions League final that year, Klopp decide to aggressively pursue an upgrade. It was a deal that simply needed to be success and the Reds boss knew it.
"We had only two signings where we thought: ‘Right, they absolutely have to be a slam dunk'. That was Ali and Virgil (van Dijk)," Klopp said earlier this year.
It’s a move that has worked out perfectly for both player and club. Within 12 months of him signing for the Reds, Alisson was a Champions League winner. He followed that up with a Copa America triumph as Brazil secured the South American crown in their homeland.
Golden Glove awards in the Premier League, Champions League and Cola America were followed up by shiny gongs from UEFA and FIFA for the increasingly decorated Alisson. It all makes a compelling case for the Liverpool superstar to be known as the world’s best goalkeeper, doesn't it?
"It is tough for me to say as a goalkeeper coach but it's definitely how I see it," says Achterberg.
"I think he has been the most consistent if you look at all the goalkeepers around, that is the truth. Now we try to maintain it and keep it like this for the next five or six years. He has set his targets and we try to push it that way, that is the plan."
After an absence of over two months, Alisson is fit to return to the Liverpool squad that travels to Manchester United after the international break. The Brazilian's deputy, Adrian, has performed admirably during his calf problem, but Klopp could re-field one of the planet's very best when his table-topping Reds visit Old Trafford on October 20.
Klopp admitted the £65m deal needed to be a "slam dunk" - Actherberg's tireless work behind the Melwood curtain was instrumental to ensuring it didn't hit the backboard.
*Part 2 of Paul Gorst's chat with John Achterberg tomorrow focuses on the Anfield careers of Adrian, Andy Lonergan and Caoimhin Kelleher
