Alan Hansen once said it could be worth 12 points a season. Sir Alex Ferguson estimated more around the 15 mark, while Brian Clough put the figure as high as 18. But they all agreed on the fact that having an outstanding goalkeeper is essential to building a successful team.

Arsene Wenger is another of football's deepest thinkers, possibly one of the greatest spotters of talent the English game has seen, yet he has suffered from an infuriating blind spot that has hampered his attempts to stay at the top of the game; the ability to either recruit or develop a genuinely world-class goalkeeper who can have this kind of transformative impact on his team.

This is why the club's pursuit of Petr Cech -- which according to the latest reports on Thursday night is moving ever closer to completion -- is so important this summer. As well as giving Wenger the chance to scratch a 13-year itch regarding the Czech, it also could finally dispel an enduring question mark lingering around his management of the club. Namely, why has he been so bad at buying goalkeepers?

It all could have been so different. Back in the 2001-02 season before Cech joined Rennes from Sparta Prague, Wenger tried to bring in the then 20-year-old as an understudy to David Seaman, only for work permit restrictions to wreck his plan. It was a fateful twist.

Had Cech joined Arsenal at that moment, the replacement for Seaman (above, pictured) could have kept the gloves for well over a decade. The succession would have been stable and secure.

But as things have turned out, Bob Wilson's warning after Seaman's departure for Manchester City has proved prophetic: "This is a desperately sad day for Arsenal," he said back in 2003. "The fans will be really sorry that it's come to this."

Upon his arrival in England in 1996, Wenger was fortunate to inherit Seaman who, along with George Graham's famous back four, formed one of the most mythologised defensive units in history. And Seaman has never been adequately replaced. Not really.

While you can point to Sol Campbell or Bacary Sagna in defence, Patrick Vieira or Cesc Fabregas in midfield, or Robin van Persie or Thierry Henry in attack, Wenger's strike rate when it comes to buying goalkeepers is strangely poor.

The first and so far only big-money goalkeeping arrival was Richard Wright, signed from Ipswich Town for £6 million in 2001, and he made a grand total of 12 league appearances before joining Everton for almost half the price just a year later. From Guillaume Warmuz through Rami Shaaban and Vito Mannone to Lukasz Fabianski, a whole supporting cast has passed through Arsenal's doors without leaving much of an impression.

Jens Lehmann made a game attempt, though. An abrasive individual but a winner, his role in the "Invincibles" of 2003-04 should not be underplayed and thanks to moments such as the save from Juan Roman Riquelme's penalty in the Champions League semifinal in 2006, his place in Arsenal's history is secure.

But combustion, not consistency was the trademark of Lehmann (left, below, pictured). He became an increasingly bizarre figure as time wore on, attempting to push over opposition players with curious regularity and eventually being replaced by Manuel Almunia.

Ah, Almunia. Entrusting the Spaniard with a place in the first XI was arguably the most glaring mistake of Wenger's Arsenal reign -- a decision which united supporters in both bemusement and frustration. Always under-qualified, his very presence in the starting XI told you everything you needed to know about Arsenal in that difficult transition period. A team with a goalkeeper of Almunia's quality could never be serious about winning the league.

Of the current crop, Wojciech Szczesny, beset by inconsistency and still rueing that sneaky smoke in the showers at Southampton, has wasted what seemed a golden chance to become the No. 1 for many years. David Ospina, for all Wenger's insistence on his statistical brilliance, just seems a bit small and slow through the air. Both good deputies, certainly, but it was stretching credulity when Wenger said in May, in response to reports about his interest in Cech: "I don't deal in ifs. We have three world-class keepers."

In truth he doesn't have any, but if things now progress as expected he might get one soon. A four-time Premier League champion; a three-time UEFA goalkeeper of the year; a player named in the team of the tournament at Euro 2004; a seven-time Czech footballer of the year; and a man who is within eight clean sheets of David James' Premier League record of 170. Cech is one of the goalkeepers of his generation.

After Chelsea's goalkeeping coach let the secret slip at the start of the week, it seems he is heading, finally, for Arsenal. Rewarded for his distinguished 11 years of service, which have been ended only by the luminous talent of Thibaut Courtois, Cech is said to have been told by Roman Abramovich that he can move to whichever club he likes.

It would probably be worth it just to see the look on Jose Mourinho's face. But Wenger also will know that 12 years after Seaman left Arsenal as the most successful goalkeeper in the club's distinguished history, he finally has a replacement worthy of taking ownership of the gloves and, hopefully, delivering those fabled 12, 15 or 18 points next season. Cech will likely prove worth the wait.

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Tom Adams writes for Eurosport. Get him on Twitter: @tomEurosport