After he decided to take over at Chelsea this summer Frank Lampard knew there were several problems to solve.
The biggest was how to replace Eden Hazard without having the option of entering the transfer market. There was also the lack of an established No.9 at the club. And the centre of defence was also somewhat understocked.
Lampard went about solving these problems, but one area that appeared a point of strength was goalkeeper.
Kepa Arrizabalaga had arrived the previous summer from Athletic Club for a world-record fee for a goalkeeper, £71.6million.
His form was solid if not spectacular. And barring his public defiance against being substituted in the Carabao Cup final, there was little to discuss when it came to the Spain international. He was effective yet understated.
Kepa ended his first season at Stamford Bridge having kept 23 clean sheets in 54 matches, an impressive return for a goalkeeper adapting to a new country, culture and club. The world-record fee Chelsea paid didn't impact his performances.
This term, however, things have been a little different. Kepa has just the one clean sheet to his name in ten matches, which came against Brighton and Hove Albion last weekend.
“After the clean sheet on Saturday, the person I was happiest for was Kepa,” Lampard explained earlier this week. “His confidence shouldn’t go down. The clean sheets are not always his own responsibility, but also when he thinks they might have been his responsibility, he is very open to accept that fact and work to improve.
“I have been really impressed with him. He’s managed to become Spain’s No.1 which when you think about who he’s competing with at that level is very serious.
“He is a great age for us in terms of where he’s at in his career. He grew as last season went on to help Chelsea win games, and I think he is growing again now. I am very happy with him as a player. If anything I can say in his role and his status within the group, he can become a bit more vocal because that’s what great goalkeepers do.”
Chelsea's defensive frailties under Lampard have been well documented – the Blues have conceded two or more goals in five of their opening seven Premier League fixtures.
Whether set up with a back four or a back three, Lampard's side has contained a soft centre. And there inability to defend set-pieces has meant Kepa has been given something of a free pass.
His form hasn't been questioned, with many observers focused on what is ahead of the Spaniard. Yet a deeper dive into the 24-year-old's underlying numbers gives reason for concern.
This season Chelsea have conceded chances to opponents worth 1.77 expected goals per 90. However, these opportunities been devalued by the opposition players. Stay with us, it gets a little complicated.
Football Whispers‘ post-shot expected goals model measures not only where a shot is taken from but also where the effort on target is placed. It, in essence, is a good way to judge goalkeepers.
So in the Premier League this season, Chelsea's post-shot expected goals against this season is 1 per 90. But their actual goals conceded, excluding own goals, is 1.57 per 90.
The 0.57 difference is huge, the worst in the English top-flight. Only Ben Foster of bottom side Watford comes close – the Hornets stopper is conceding 1.43 goals for every 1 post-shot expected goal against.
What does this suggest? Well, the sample size is small and there is the unquantifiable variable of luck, but it appears Kepa is somehow improving the likelihood of an opposition shot hitting the back of the net.
It wasn't always this way, though. Kepa's first season at Stamford Bridge following his world-record transfer from Athletic Club was solid if not spectacular.
Chelsea conceded 1.03 goals per 90 in the Premier League last term but their expected goals against per 90 and post-shot expected goals against per 90 were 0.93.
So through his goalkeeping, Kepa was reducing the quality of the shots he faced by 0.10. That is, obviously, far better than he's managed this season.
It's why Lampard shouldn't – and more importantly won't – make a drastic decision over his No.1 goalkeeper. There needs to be an improvement from Kepa, of that there is no doubt. But it's likely his underlying numbers level out somewhat in the coming weeks.
If they don't…well, Lampard will have another problem to solve, one he certainly wouldn't have seen coming.