It was a particularly big day at Chelsea, as under-pressure head coach Frank Lampard, who was battling to save his job, was finally sacked in the late hours of Monday morning, barely 24 hours after a win over Luton Town in the FA Cup.The 3-1 victory over the weekend in the FA Cup was not enough to save his job, as the Blues had been on a woeful run in the Premier League.After Chelsea owner Roman Abramovich opted to make the key decision, it appears Thomas Tuchel is the man stepping into the dugout at Stamford Bridge, after talks were reportedly held over the weekend.Thomas Tuchel to oversee new era at ChelseaThe German head coach is already well-known by a few players in west London, with Thiago Silva and Christian Pulisic playing under his tutelage at Paris Saint-Germain and Borussia Dortmund respectively.Thomas Tuchel is set to become the new Chelsea manager, confirmed. Frank Lampard will be officially sacked today - Tuchel has accepted the #CFC job and is expected to sign in the coming hours. 🔵RB Lepzig won’t let Nagelsmann go now + Allegri is considering other options/clubs. https://t.co/KODPcJAFF5— Fabrizio Romano (@FabrizioRomano) January 25, 2021However, with Tuchel having less than a week to do any real business in this transfer window, it's difficult to see any new signings at Chelsea, meaning the 47-year-old would have to select from the pool of players already at the club.With such a large squad, several players are likely to be deemed surplus to requirements, and here are five stars who could be cast aside by Thomas Tuchel.#5 Marcos AlonsoBrighton & Hove Albion v Chelsea - Premier LeagueThe 30-year-old left-back had already seen his spot under threat with the arrival of Ben Chilwell in the summer, before getting into a worse situation by falling out with outgoing manager Frank Lampard.The Spaniard hasn't appeared for Chelsea since September after that, and it should not come as a surprise if he continues to be overlooked even by the new manager after being out of action for such a long period.#4 Kepa ArrizabalagaChelsea v Morecambe: FA Cup Third RoundThe Spanish international has never been far from the media after his €80 million move from Athletic Bilbao in the summer of 2018, where he became the most expensive goalkeeper of all time.However, he has grossly fallen short of expectations that come with such a price tag over as his time at Chelsea and has been responsible for several horrendous errors leading to opposition goals.58.8% - Since the start of last season, Kepa's save percentage of 58.8% is the lowest of any Premier League goalkeeper with 20+ appearances in this period. Rut. pic.twitter.com/MN2vVhVClB— OptaJoe (@OptaJoe) January 24, 2021His spot as Chelsea's first-choice goalkeeper has since been given to the Senegalese summer signing Edouard Mendy, but he still has not been remarkable as the team's backup goalkeeper, meaning Tuchel might opt for a more tested and reliable option in veteran Willy Caballero.