On his first Monday in his new job, Mauricio Pochettino should this morning watch out for the revolving door at <a href="https://www.thenationalnews.com/tags/chelsea-fc/" target="_blank">Chelsea</a> headquarters. As he settles in as manager, he can anticipate as many farewells as greetings, his urgent challenge to reduce the wild guesswork around what his first line-up will look like come mid-August and the opening fixture of the new Premier League season against Liverpool. Pochettino inherits a squad where high turnover has become endemic. Less than 10 months ago, when Thomas Tuchel, one of four different men to have managed Chelsea since last September, took charge for the last time, he had a central midfield of Mateo Kovacic and Mason Mount, supplemented by Jorginho in the later stages of a <a href="https://www.thenationalnews.com/sport/football/2022/09/07/dinamo-zagreb-v-chelsea-player-ratings-petkovic-9-orsic-8-fofana-4-mount-3/" target="_blank">shock 1-0 defeat at Dinamo Zagreb</a>. That trio had served Tuchel in the winning final of the 2021 Champions League; in Croatia, Tuchel would have like N’Golo Kante involved and regretted the absence, through injury, of the Frenchman who, said Tuchel, “who simply makes players better around him.” Up front in Zagreb were Kai Havertz and the then new recruit Pierre-Emerick Aubameyang. Kalidou Koulibaly, <a href="https://www.thenationalnews.com/sport/football/2022/07/16/kalidou-koulibaly-signs-four-year-deal-with-big-team-chelsea/" target="_blank">freshly signed from Napoli</a>, joined Cesar Azpilicueta in an experienced back three. Edu Mendy had been left out from the previous fixture to give the goalkeeping gloves to Kepa Arrizabalaga. As Tuchel chased in vain an equaliser, Hakim Ziyech came on, as did Christian Pulisic. By this September, Pochettino expects to be giving instructions to none of those players except perhaps Kepa, a measure of the extraordinary instability and churn of personnel at Chelsea – a club that changed ownership in May 2022 and has since spent over £650 million on transfer fees, appointed two ‘permanent’ and two interim managers and finished 12th in England’s top division, an all-time low in the 31 years since the Premier League came into being, and far too low to qualify for Europe. The revolving door turned fast for Koulibaly, who has joined the caravan of stars to <a href="https://www.thenationalnews.com/sport/football/2023/06/26/kalidou-koulibaly-joins-ruben-neves-at-saudi-pro-league-side-al-hilal/" target="_blank">Saudi Arabia’s Pro League, signing for Al Hilal</a> for around half the £33 million Chelsea paid for him. Aubameyang – who made a mere five Premier League starts last season – is up for sale and may head to the same league, where <a href="https://www.thenationalnews.com/sport/football/2023/06/21/ngolo-kante-very-excited-to-join-karim-benzema-at-saudi-pro-league-champions-al-ittihad/" target="_blank">Kante (Al Ittihad, on a free)</a> and <a href="https://www.thenationalnews.com/sport/football/2023/06/28/chelsea-wish-edouard-mendy-good-luck-after-signing-al-ahli-deal/" target="_blank">Mendy (Al Hilal, for £16 million)</a> will both now be pursuing their careers. Azpilicueta, 33, looks set to move back to his native Spain, while Ziyech is also being pushed to an exit. Pochettino has been promised a fresh start by his new bosses, but there are constraints. Chelsea’s heavy spending over the last two transfer windows and the projected revenue adjustments caused by playing in no Uefa competitions in 2023/24 oblige the club to be mindful of Financial Fair Play limits on the ratio of expenditure to income. And Chelsea have become a harder sell for the class of player for whom involvement in Europe – preferably the Champions League – is a prerequisite. Kovacic will play in the Uefa Champions League next season, as will Mount, Havertz and Jorginho. That quartet have all joined clubs who finished in England’s top four in May, and have ambitions to add to the European Cup medals they won under Tuchel with Chelsea. Kovacic has the best chance,<a href="https://www.thenationalnews.com/sport/football/2023/06/27/mateo-kovacic-completes-25m-move-from-chelsea-to-manchester-city/" target="_blank"> having joined Manchester City</a>. <a href="https://www.thenationalnews.com/sport/football/2023/06/30/manchester-united-agree-55m-deal-to-sign-mason-mount-from-chelsea/" target="_blank">Mount’s imminent move to Manchester United </a>meanwhile marks a significant crossroads for the Chelsea he grew up with – a genuine home-grown star has been sold. The see-saw of shifting power in London is emphasised by <a href="https://www.thenationalnews.com/sport/football/2023/06/29/kai-havertz-excited-to-join-arsenal-family-after-completing-65m-move-from-chelsea/" target="_blank">Havertz’s agreeing to join Arsenal</a>, as Jorginho did in January. Once the Mount deal is finalised, at around €60 millon, Chelsea will have brought in £150 million from rival Premier League clubs, with Arsenal paying £65 millon for Havertz and City £25 millon for Kovacic. Whether they thrive in the way other famous past Chelsea discards, such as Kevin de Bruyne and Mohamed Salah, did will be Pochettino’s concern only if Arsenal, City and United further consolidate their status in the upper rungs of the Premier League and again leave Chelsea trailing them outside the top four. Havertz was Chelsea’s top scorer last season, and by the close of the summer window, he will likely be one of a number of attacking players to have departed. Aubameyang is studying exit options while AC Milan, who have already <a href="https://www.thenationalnews.com/sport/football/2023/06/27/ruben-loftus-cheek-set-to-join-chelsea-exodus-as-he-closes-in-on-ac-milan-move/" target="_blank">signed Ruben Loftus-Cheek from Chelsea</a>, are keen on Pulisic. But Pochettino’s preseason will be boosted with two incoming strikers, <a href="https://www.thenationalnews.com/sport/football/2023/06/20/chelsea-announce-signing-of-christopher-nkunku-from-rb-leipzig/" target="_blank">Christopher Nkunku</a> and <a href="https://www.thenationalnews.com/sport/football/2023/07/01/chelsea-overhaul-continues-as-they-sign-nicolas-jackson-from-villarreal/" target="_blank">Nicolas Jackson</a>, signed for a combined £80 million-plus from RB Leipzig and Villarreal. They are internationals, with France and Senegal, and 25 and 22 years old, so in the same age bracket as midfielder Enzo Fernandez, wingers Mykhailo Mudryk and Noni Madueke and defenders Benoit Badiashile and Wesley Fofana, on whom huge money was invested during the rollercoaster 2022-23. Around those young talents, Pochettino can see the spine of an exciting, energetic side, but he will need a period of calm and patience to properly cultivate it.