When links between Chelsea and Kai Havertz first emerged, it raised a few eyebrows. Chelsea had just spent a boatload of money on Hakim Ziyech and Timo Werner, so there didn't really appear to be a spot for Havertz in the squad on paper.
The thing with Havertz is that he's one of those players that you sign first and ask questions about later.
If you ask Chelsea fans now how they expect to see the 21-year-old deployed at Stamford Bridge, you'll get plenty of different answers. Will he play in central midfield? Behind the striker? Over on the right wing?
There's a good chance he'll occupy all three roles at one point or another, and he's good enough to look at home wherever he ends up.
Werner started in attack but often drifted out wide, as is to be expected from the German. During his final season with RB Leipzig, he often dropped deeper into midfield or strayed out to the wing to create space for other teammates to rotate into a more central role.
When Werner was on the left wing, there was a clear and obvious effort from central midfielder Ruben Loftus-Cheek to get into the box and operate as a striker. He would drag defenders around by leaving his typical position and gave Chelsea a focal point, and that's your Havertz role right there.
Stealing the show as a central striker towards the end of the Bundesliga season, Havertz is more than comfortable operating in that advanced role and will give Chelsea the kind of goal threat from deep which Stamford Bridge hasn't seen since Frank Lampard's playing days.
Rotation and fluidity look to be key in Lampard's side. Werner starts central but heads left, Havertz starts deep and drives forward and Ziyech starts wide and drifts inside. It's a defender's nightmare as it's impossible to manage.
When in possession of the ball, the German can do pretty much whatever he wants.
Whether it's combining with other midfielders with intricate passing or using his terrifying blend of agility and power to bully defenders, Havertz can force himself forward and make things happen with a frightening lack of effort.
He'll look for those runs from Werner, Ziyech and Pulisic and he'll drop the ball off when needed, but if he doesn't like what he sees, he'll make the chance himself.
For too long, Chelsea's only real goal threat has come from forwards. It's why Mason Mount's emergence was a breath of fresh air and why Ross Barkley has his own set of supporters at the Bridge. They both stop Chelsea from looking one-dimensional.
But Havertz brings his own dimension.
He's the final piece in Lampard's attacking puzzle. Now, the focus is on making sure all the cogs gel in the machine as soon as possible. Once Chelsea are up to speed, the results could be devastating.