Everton have confirmed the signing of Lyon defender Jake O'Brien who arrives in a deal worth £17m.
The 23-year-old becomes the Toffees fifth signing of the summer and has penned a four-year deal at the club.
O'Brien starred in his first season in Ligue 1, having made 27 appearances as Lyon qualified for the Europa League after a poor start to the campaign.
His exploits had caught the eyes of several Premier League sides but it was Everton who managed to strike a deal - with the backing of £70m already made from player sales this summer.
The defender's arrival signals Everton's first reinforcement in that area. Ben Godfrey's move to Atalanta and the continued suggestions of a Manchester United switch for Jarrad Branthwaite meant that central defence was always a position of concern.
With that in mind, O'Brien's move makes plenty of sense but will it have a domino effect on how the Blues back four will shape up?
What does O'Brien bring?
Last season, Sean Dyche largely stuck to a partnership of Branthwaite and James Tarkowski for their ability to be aggressive, progressive when needed while being aerially dominant.
It was clear that the depth behind that was an issue with only Michael Keane trusted to rotate with the starting two. O'Brien's pedigree brings competition to those starting places and it is easy to see why with his attributes.
A right-footed centre-back, O'Brien is comfortable playing on both sides and has the physical capabilities needed for the Premier League stage.
Standing at 6'6, he is an imposing defender who is aerially dominant in both boxes. He also has good athleticism, with a quick turn of pace to go alongside his intelligence to cover spaces and win duels.
On the ball, he can progress play especially with his long-range passing. Among centre-backs in Europe's top five leagues, O'Brien ranks in the 94th percentile for completed long passes - a figure that would serve well in Dyche's direct style.
The defender can also impact things going forwards, notching an impressive four goals in the league last term - the second highest in the Lyon team behind Alexandre Lacazette.
His qualities display a potential to be a game-changer at the back for Everton, but just how has he become the perfect match?
His career so far
O'Brien began his career at Cork City where he made 12 appearances for his hometown club before making the move to Crystal Palace back in 2021.
His time in South London saw him fail to make a senior appearance for the club and instead loaned out to Swindon Town in League Two.
The defender impressed there, making 21 appearances in their run to the play-off semi-finals, although his season ended early due to injury.
Belgian second-tier side RWD Molenbeek then took him on loan the following season, with O'Brien an important cog of their promotion back to the Pro League for the first time since being reformed.
That prompted Lyon to sign the Crystal Palace defender on a four-year deal for an undisclosed fee in August 2023.
After a promising couple of seasons, it was at Les Gones where he managed to showcase his potential.
The Irishman made 32 appearances across all competitions as he captured the attention of many, both at club and country with his superb defensive displays.
In just one season at the club, his talent has proved good enough for the Premier League with the Toffees tabling a £17m fee for his services.
An excellent deal to bring him in but could be the tipping point for Branthwaite to be sold.
One in, one out maybe?
Everton have remained adamant that this deal has no impact on Branthwaite's future and it is more a case of adding to the squad.
O'Brien's arrival would leave Dyche with a healthy number of five senior centre-back options if Branthwaite decided to stay.
The figures would also make sense if the defender decided to leave however.
Everton's current sell-to-buy policy would mean a rumoured sale of £70m for Branthwaite compared to £17m for O'Brien could allow the club some breathing space in an uncertain time.
This was posed to Dyche, who remained clear on the club's transfer plans after Everton's pre-season friendly defeat to Coventry.
He said: "It's just to do with trying to model the club with the finances available, trying to bring players that can add the layers to the club.
"Obviously we're stretched at the moment with depth. Younger players who can develop and protect the club on the pitch with their performances, then in the future with the finances.
"We've made it clear to him [Branthwaite] that it's nothing more than that, but of course put two and two together and everyone starts speculating. What do you do?"
How does O'Brien fit at Everton?
With the idea that Branthwaite will stay, it would suggest that O'Brien would have his work cut out to become a starter.
Dyche's preference to play a back four means it is a battle for two starting spots. If O'Brien was to play on the left side of defence then he would directly replace Branthwaite, who provides natural balance being a left-footer.
While on the right-side is vice-captain James Tarkowski, who played every league game for Everton last term. The stats would signify his importance and despite being 32, it would seem unlikely that Dyche would drop him for a younger partnership.
Regardless of whether he starts or not, O'Brien would add more competition and provide rotational cover to a key position.
The intense nature of the Premier League calendar added to the domestic cup competitions would mean that he would get plenty of playing time.
O'Brien's arrival will continue to pose the questions of who stays and who goes, but it's clear that the Irishman solves a problem that Everton needed to fix.
