The Surprising Best Goalkeeper In The Premier League This Season

(All statistics correct as of 4th December 2023)

The English Premier League is home to a string of world-class goalkeepers but new data from fbref.com suggests a lesser-known talent from Luton Town is statistically out-performing them.

Alisson, André Onana, Ederson, and even Argentina’s World Cup winning hero Emiliano Martínez move over and make way for Thomas Kaminski.

Thomas Kaminski is only in his first season at newly promoted Luton Town having signed from Blackburn Rovers in the summer for around £2.5 million- over 25 times less than the reported record transfer fee of a goalkeeper to a premier league team.

Despite conceding the joint 3rd most goals in the league, the Belgian goalkeeper has prevented his team from conceding far more than expected, according to fbref.com data.

This is all down to a statistic called post shot expected goals (PSxG), also known as expected goals on target. The statistic is an extension of the expected goals model (xG).

xG ranks the likelihood of a shot to score. The model takes into account variables such as the distance and angle of the shot to goal, the number of players between the shot and the goal, and the type of shot.

For example a shot taken far away from the goal where there are also multiple opposition players in the way will have a low value like 0.02- meaning the shot has a 2% chance of being a goal. A shot 1 metre from the goal with no players in the way might have a value of 0.93- 93% chance of scoring.

Each shot is different and the model is based on a large and constantly expanding data set of hundreds and thousands of shots.

The difference between xG and PSxG is that the latter factors in what happens just after the ball has been kicked. Take the last example, where the shot had an xG of 0.93 – if the player slipped over when taking the shot, the chance of scoring would dramatically decrease, and maybe have a PSxG of around 0.45.

Traditional statistics commonly used to assess the ability of a goalkeeper, such as clean sheets or save percentage, can be affected by outside factors, such as the quality of the defence in front of the goalkeeper.

PSxG effectively cuts out all other interference and assesses only the chance of any particular shot scoring. If a goalkeeper saves two shots, one with a PSxG of 0.87, and one worth 0.12, the higher value shot is much harder to save.

If you take the total number of PSxG a goalkeeper has faced and then take away the actual number of goals they have conceded; you get a very good indication of how good a goalkeeper is at saving the shots that they face. This statistic is called PSxG-GA. Note that own-goals are excluded from it.

In Kaminski’s case, he has 29.1 PSxG against him, and has conceded 26 goals (1 being an own goal). The Belgian goalkeeper therefore has a PSxG-GA of +4.1, which is the best in the league.

There are a few goalkeepers close to Kaminski in this statistic, namely André Onana and Alisson. However, what makes the Luton player stand out is the average quality of each shot against him. Dividing PSxG by the total number of shots faced gives you PSxG/SoT.

As shown in the above graph, Thomas Kaminski faces shots which are over 30% harder to save than the shots faced by Onana and Alisson. This makes his goal prevention numbers all the more impressive.

Luton Town fans will be hoping their goalkeeper will continue to perform at a high level, as they attempt to avoid relegation from the Premier League.