Chelsea completed a head-spinning January transfer window by making Enzo Fernandez the most expensive player in British football history on deadline day.After nearly a month of haggling with Benfica, Todd Boehly and the new Chelsea hierarchy that is causing plenty of bafflement at the elite level of the sport managed to get a 106.8 million ( Kyler Murray T Shirts 121m) deal over the line for the Argentina World Cup star.At Stamford Bridge, the hope will be that head coach Graham Potter can benefit from the additions of Fernandez, Mykhailo Murdryk, Joao Felix, Benoit Badiashile, Noni Madueke, David Fofana and Andrey Santos.Fullback Malo Gusto has been loaned back to Lyon for the remainder of the season after joining during the final week of the window, but the other seven signings will vie for their place in Potters plans.Premier League squad rules mean all of Chelseas January buys will be able to take part as Potter attempts to plot a path upwards from 10th in the table. In the Champions League, where Chelsea face Boru sia Dortmund in the first leg of their last-16 tie this month, things are a little more complicated.MORE: Clubs submit two squad lists to UEFA at the start of each season, List A and List B.List A can have up to 25 players, a minimum of two goalkeepers and eight locally-trained or homegrown players. Of those, at least four must be club trained.List B can feature an unlimited number of players born after January 1, 2001. The clued-up among up you will note that distinction applies to every January signing Chelsea have made aside from Atletico Madrid loanee Joao Felix. Happy days!But hold your horses. While those players can simply be listed as U21s with the Premier League and play without any i sues, List B players must have played for a club for two uninterrupted years or Anquan Boldin Jersey three consecutive years with a maximum of one loan period not longer than a year.So Boehly and Potters new recruits are only List A eligible and UEFA stipulates that clubs can add a maximum of three new players when they submit squads for the second half of the season. These squads must be finalised by Thursday, February 2 this season.Chelseas squad for the group stages had 24 List A players. Jorginho joined Arsenal on deadline day and if Hakim Ziyechs loan switch to Paris Saint-Germain hadnt run into 11th-hour problems, it would be a simple question of filling three free spots. Getty Images As it is, Potter must cut one senior player from his Champions League squad to include three new signings. Ziyech would appear to be the obvious candidate given this weeks events, although injury absentees Wesley Fofana and Christian Pulisic could also be cut.Armando Broja is a long-term absentee but features on List B, so cannot lighten the load. Denis Zakaria, who is on loan from Juventus, could be left out as he is unlikely to form part of the long-term plans, although Jorginhos departure means Potter might be wary of leaving himself light in central midfield.MORE: Despite the youthful makeup of Chelseas splurge, the newcomers do not lack for Champions League experience.Mudryks caught the eye for Shakhtar Donetsk during this seasons group stage, scoring three goals and supplying two a sists in six matches.Despite only being 23 himself, Joao Felix is something of an old hand on the European stage, although he did not score in five appearances this term. That arguably does much to explain why Atletico Madrid failed to progre s and Diego Simeones willingne s to let the Portugal forward leave on loan.Fernandez and Benfica did Tanner Vallejo Jersey make the last 16 but his efforts for Roger Schmidts side will not preclude him from taking part for Chelsea at the busine s end of the competition.Players who featured for another club in the same season used to be cup-tied in UEFA competitions but, since 2018/19, that has no longer been the case. So the fact Benfica made the knockouts and Shakhtar and Atletico didnt is by the by. Fernandez, Murdryk and Joao Felix are all eligible to be named in Potters squad.Likewise, Badiashile and Madueke playing for Monaco and PSV in the Europa League and David Fofana representing Molde in the Europa Conference League this term does not come into the calculations. MORE: Despite not being loaned before the deadline, David Fofana and Santos are the two signings who can most obviously be filed under the heading ones for the future, so much so that it would be a huge surprise to see them in Chelseas Champions League squad.Madueke set Boehly back 29m but similarly feels like a project player and joins the most lavishly stocked part of the Chelsea squad. Even with Pulisic sidelined the club were happy to try to move Ziyech on. The reason being they are stacked in terms of wide attackers.The most expensive of all of those is Mudryk. In his debut cameo for Chelsea in the goalle s draw at Liverpool, he injected a verve badly lacking from the injury-hit Blues over recent weeks.The Ukraine winger is a player on the crest of a wave with a taste for shining in the Champions League. As much as he signed Justin Murray Jersey a ma sive eight-and-a-half-year contract, he is also a man for now.Fernandez is the no-brainer selection, if only for the fact he replaces Jorginho as a midfield body before we consider the automatic status that comes with his gargantuan transfer fee.The 22-year-old Argentina star will clearly become a central part of this new Chelsea era with immediate effect.With two down and one to go, we come to a bit of a conundrum. Felix sparkled on his Chelsea debut before soiling it spectacularly by getting sent off in the 2-1 defeat to Fulham. GAMING SURVEY: In Badiashiles case, there is not such a mixed early report card. The 21-year-old defender came into a team on a run of three consecutive defeats. Since his inclusion, Chelsea have kept two clean sheets with Badiashile playing all 180 minutes against Crystal Palace and Liverpool.That immediate impact feels significant, especially given Kalidou Koulibalys patchy adaptation to life in west London since his close-season arrival from Napoli. The masterful Thiago Silva has struck up an instant rapport with Badiashile.Chelsea have neither an option nor obligation to buy Joao Felix when his loan concludes and the picture has changed radically since Michael Dogbe Jersey he trudged off at Craven Cottage. If Kai Havertz and Pierre-Emerick Aubameyang were perfect solutions at centre-forward, Chelsea would not have signed the Atleti man in the first place.However, the other three major signings mentioned clearly have a huge future at Stamford Bridge. Badiashiles instant impact and Chelseas relative attacking and defensive depth means the left-sided central defender should get the nod.