Alisson Emerged as Europe's Top Keeper This Year

What a difference a year makes.

Last year, Alisson played second fiddle to Szczesny, who earned plaudits as one of the top keepers in Serie A. Alisson, on the other hand, had 15 unremarkable appearances in Roma’s cup campaigns, which were riddled with individual errors and early exits. It is not surprising, then, that most of us saw Alisson as an uninspired choice at best and a major step backwards at worst. Naturally, Szczesny followed the well-trodden path to Juventus for a seemingly rock bottom transfer fee of €16 million, as Juventus continued their strategy of poaching top players from their rivals for pennies on the dollar. At the time, it felt like our current FFP woes forced us into strengthening Juve at our expense, but now it seems that Monchi just had another, better idea.

Just 12 months later, our Brazilian Don Draper is headed to the world cup as Brazil’s starting keeper, amid constant transfer talk about a bidding war between Real Madrid and Liverpool, who are fighting over who gets to pay the biggest transfer fee ever for a keeper. These outrageous transfer fees of €70 or €80 million reflect the extraordinary year Alisson has had. It is not surprising that he is in the conversation of best keeper of the year if you take a look at his stats.

Whoscored rates Alisson as the best keeper, hands down, across the top 5 leagues for all keepers who played at least 15 games. Squawka puts Alisson at a close 2nd to ter Stergen who had the benefit of playing for the almost-but-not-quite undefeated Barcelona side (not counting their memorable defeats in the Champions League, of course). Alisson’s performances are pretty damn impressive any way you slice it, but especially considering that Roma doesn’t always make it easy to do as well on stats that are more dependent on team performance (e.g. clean sheets).

So, why is he rated so highly? Let’s break it down.

Alisson was quite possibly the best sweeper keeper in the game this year. That may be in part because Neuer was out with injury, but it is undeniable that Alisson is one of the best keepers at building up from the back. Pep Guardiola famously demands that his keepers have the passing skills of midfielders, which is why Manchester City has spent around €63 million in the last two years on keepers who are good with their feet. Yet, a comparison of Man City’s current number 1, Ederson, to Alisson found that they are roughly equally skilled with short passes, but Alisson outperforms Ederson with mid and especially long-range passing. This is particularly impressive because Ederson attempts long passes less often as it goes against Pep’s philosophy, so Alisson can’t afford to be as selective as Ederson when picking out a long pass.

Of course, keepers are not actually midfielders, and they earn their keep with their defensive ability. Here, too, Alisson has outshined the best of them. Goalkeepers are especially prone to being over or underrated based on how difficult their saves look, which can make theatrical or poorly positioned keepers look like rockstars. So, here we take a look at some stats to get a clearer, more objective sense of his performance.

Specifically, we look at expected goals against (xGA). Expected goals (xG) are computed by identifying the position a shot was taken from and calculating the likelihood that a player would score from that position. So, xGA are the expected goals (xG) for the opposition. xGA is the perfect measure of how a goalie performed (for shot stopping) because, over the course of a year, they will face shots from all kinds of different strikers. Therefore, any differences in the skill of strikers should wash out by the end of the year. As a result, the difference between actual goals against (GA) and xGA effectively measures how well a goalie stopped shots in a season. This is how we analyze Alisson’s performance.

Below, there is a table that includes the goals against (GA), expected goalst against (xGA), and the difference between them for each game of the season. Amazingly, Alisson outperformed the xGA in 30 of the 37 games this season, combining for a total of 9.46 fewer goals against than we would expect with a typical keeper. By comparison, Szczesny only outperformed his xGA in 11 of the 17 games he played. He would have to play another 20 games and only flub one of them to be as consistent as Alisson has been this year.

The table also includes the expected points based on how many points Roma would have earned if we ignore the actual goals against and just consider the expected goals against. Basically, how many points would we have earned if we had a generic, typical goalie and not our very own gladiator in net? From this, we calculate the change in points earned for the game.

What we find is that Alisson, on his own, kept us from dropping 10.92 points that we probably otherwise deserved to drop. This helps to explain how Roma performed so well overall while delivering what felt like underwhelming performances so often throughout the season. In particular, during the mid-season lull, Alisson was propping up the team left and right by single-handedly saving points in 11 of 16 matches. What is even more extraordinary, of the 16 matches that he had a decisive impact, 15 of them were saving points that we should have lost. On the other hand, Szczesny had a decisive impact on 9 of his 17 matches, and 2 of them were dropping points that Juventus otherwise had earned. More than that, Szczesny generally played against lower quality teams, facing weaker strikers, which again emphasizes just how good of a season Alisson had.

If we just remove Alisson’s unique shot stopping ability and assume we had a typical goalie, we would be on 66 points, just barely pipping Milan for 6th place. That doesn’t even take into account his other defensive contributions or superb distribution.

Of course, it is not that straightforward to know what would have happened without Alisson because poor results can breed more poor results, so without his consistent performances in net, it is more than likely that players would have let their heads drop and more points would have followed. Also, Alisson wouldn’t have been replaced by a generic xGA keeper, and it is possible that Skorupski would have done fine and possibly outperformed the xGA as well. But, it’s very unlikely he, or anyone else we could have brought in, would have outperformed the xGA to this extent or assisted build up play as much as Alisson did.

All in all, it is safe to say we would have, at the very least, missed out on the Champions League next year without him. It isn’t often that you can so definitively say that about a single player. And, that is why Alisson has been, without a doubt, the savior of Rome this year.