Mauricio Pochettino's side have apparently agreed a deal worth £23.2m for the tough-tackling Frenchman, who will become their fifth arrival of the summer after Nicolas Jackson, Christopher Nkunku, Diego Moreira and Angelo Gabriel.
A loan move to sister club Strasbourg - who are managed by Premier League-winning midfielder Patrick Vieira - is not beyond the realm of possibility, but Chelsea are noticeably thin on the ground in the centre of the park, and Ugochukwu could therefore be integrated into the first-team setup straight away.
Should the latter scenario come to fruition, Sports Mole takes a look at which shirt numbers could be available to Ugochukwu at Chelsea for the 2023-24 season.
Despite his tender age and relative inexperience at the top level, Ugochukwu has already been bestowed with the traditional number six jersey for defensive midfielders at Rennes - a shirt he donned during the most recent campaign with Rennes.
The teenager has also sported the same number for France's Under-19 team, but that shirt has typically been reserved for defenders at Chelsea, including Ugochukwu's compatriot Marcel Desailly and Ricardo Carvalho.
As of 2023, the '6' is in the possession of Thiago Silva at Chelsea, and while a few unsubstantiated rumours of the Brazilian possibly seeking pastures new this summer were swirling, Silva is now expected to stay on at Stamford Bridge for another year.
The 38-year-old's anticipated departure in 2024 would leave the '6' up for grabs, meaning that Ugochukwu could have a clear run at Silva's shirt if a Strasbourg loan materialises this summer, but the midfielder will seemingly need to have a look at alternative options this time around.
Before taking on the number six shirt for Rennes, Ugochukwu stepped out onto the field with the '13' and '15' on his back, but those shirts belong to Marcus Bettinelli and Mykhaylo Mudryk respectively in West London.
However, Chelsea's spate of summer exits has left a plethora of notable numbers awaiting their next owners, including the number eight shirt, which Ugochukwu has previously sported at youth level for club and country.
The shirt once donned by Ray Wilkins, Frank Lampard and Mateo Kovacic would be an appropriate pick for Ugochukwu, but if Chelsea can still pull off a big-money deal for Brighton & Hove Albion's Moises Caicedo, one anticipates that the Ecuadorian will be given first refusal.
Nevertheless, N'Golo Kante's old '7' is on offer, while the number two, three, 12, 16, 19 and 20 shirts have also been left vacant, offering Ugochukwu an extensive selection from which to choose from.