The position of goalkeeper is one of the most specialised ones in a football field. A goalkeeper enjoys certain privileges that other outfield players don't.
Unlike an outfield player, a goalkeeper can use his hands inside his penalty box to keep the opposition from scoring while being the last line of defence for his team. For that reason, a mistake by a goalkeeper more often than not results in a goal for the opposition.
As the only mandatory position in a football field, a goalkeeper wears a different jersey compared to his teammates. When the starting goalkeeper is sent off, a substitute goalkeeper takes their place; but if a team exhausts its substitutions, an outfield player becomes the goalkeeper as the position cannot be left vacant.
Considering their unique vantage point on the field, it is not uncommon for teams to have the goalkeeper as their captain. Many successful club and national teams over the years have entrusted captaincy responsibilities on their goalkeepers. Some notable examples in this regard are Manuel Neuer of Bayern Munich, Hugo Lloris of Tottenham Hotspur and Jose Luis Chilavert of Paraguay.
Ten most valuable active goalkeepers in world football
Goalkeepers have become an integral part in a team's buildup play in recent times, with the term 'sweeper-keeper' gaining popularity since the turn of the millenium.
The success of a goalkeeper often translates to success for the team. In this regard, goalkeepers can arguably be considered the most vital cog in a side, with more and more top sides willing to spend the big bucks for their last line of defence, which was not the case in the not too distant past.
On that note, let us have a look at the ten most expensive custodians who are active in the sport.
#10 Bernd Leno (Arsenal/Germany) - €32 million
The 28-year-old, who appears for the London club in the Premier League, has kept 21 clean sheets in 74 games in all competitions for Arsenal. Leno recently drew praise from Liverpool manager Jurgen Klopp for his heroics in the EFL Cup where Arsenal eliminated the reigning league champions in a penalty shootout.
The German custodian had previously made his name at Bayer Leverkusen where he kept an impressive 100 clean sheets in 304 games in all competitions during a seven-season stint at the club.
Leno, who is currently the understudy of Manuel Neuer and Marc Andre Ter Stegen in the German national team, has kept two clean sheets in eight appearances for the four-time world champions.
#9 Wojciech Szczesny (Juventus/Poland) - €35 million
Poland number one Wojciech Szczesny keeps a clean sheet almost every two games in all competitions for Juventus, managing to shut out the opposition 46 times in 101 games so far - a tally that includes 33 clean sheets in the Serie A.
Of course, the former Arsenal and AS Roma man immensely benefits by having one of the sturdiest defences in Europe in front of him, but the 30-year-old's class and attributes are unmistakable.
Last season when the Bianconeri's defensive fallibilities came to the fore in an unfamiliar zonal-marking defensive system under Maurizio Sarri, Szczesny was left exposed more often than as is usually the case. Nevertheless, the keeper provided an emphatic statement of his pedigree by making the most saves in Serie A last season as he played a key role in Juventus lifting an unprecedented ninth consecutive league title.
Unsurprisingly, Szczesny is also the first choice goalkeeper for Poland, keeping 21 clean sheets in 47 games while conceding less than a goal per game.
#8 David de Gea (Manchester United/Spain) - €35 million
David de Gea may have had an underwhelming season with Manchester United last campaign considering his staggering standards, but the 29-year-old remains the first-choice goalkeeper for both club and country.
The former Atletico Madrid custodian has been one of the few shining lights at the Old Trafford club since the departure of the club's legendary manager Sir Alex Ferguson. During a near decade-long stint at Old Trafford, De Gea has kept 143 clean sheets in 408 games in all competitions for the club.
The long-serving Manchester United number one may have hogged the limelight in recent times because of his prolonged indifferent form, But on his day De Gea is one of the best in the business, which explains why Ole Gunnar Solskjaer has not run out of patience with his goalkeeper.
Since making his debut for Spain in 2014, De Gea has kept 21 clean sheets in 45 games in all competitions for La Furia Roja, a tally that comprises of 16 shutouts in 31 competitive fixtures.
#7 Andre Onana (Ajax/Cameroon) - €36 million
Andre Onana is one of the brightest young goalkeepers in the game at the moment.
The 24-year-old Cameroon international has made his name at Eredivisie side Ajax where he has kept an impressive 76 clean sheets in 182 games in all competitions. Onana's exploits, particularly in the last two seasons, have been instrumental in Ajax's successful domestic campaigns.
The Ajax goalkeeper has also kept eight clean sheets in 15 appearances for Cameroon.