Chelsea have parted ways with Frank Lampard, with sources telling ESPN they are set to appoint Thomas Tuchel as his successor.
They informed the players not to come to the club's training base at Cobham for their planned morning session while a formal statement was prepared.
"This was a very difficult decision for the club, not least because I have an excellent personal relationship with Frank and I have the utmost respect for him," owner Roman Abramovich said. "He is a man of great integrity and has the highest of work ethics.
"However, under current circumstances we believe it is best to change managers. On behalf of everyone at the club, the board and personally, I would like to thank Frank for his work as head coach and wish him every success in the future.
"He is an important icon of this great club and his status here remains undiminished. He will always be warmly welcomed back at Stamford Bridge," Lampard said.
Lampard said in a statement that he was "disappointed" to not have been given more time, but thanked Abramovich for the opportunity.
"It has been a huge privilege and an honour to manage Chelsea, a club that has been a big part of my life for so long.
"Firstly, I would like to thank the fans for the incredible support that I have received over the last 18 months. I hope they know what that means to me.
"When I took on this role I understood the challenges that lay ahead in a difficult time for the football club.
"I am proud of the achievements that we made, and I am proud of the academy players that have made their step into the first team and performed so well. They are the future of the club."
The delayed session was subsequently taken by first-team coaches Joe Edwards and Anthony Barry as Chelsea continued to finalise contract talks with Tuchel, who has been out of work since December after parting company with Paris Saint-Germain.
The German is in London to finalise terms on a multi-year contract. Presuming Tuchel tests negative for COVID-19 and there are no other last-minute hitches, he is expected to hold a news conference on Tuesday and will take charge of the team for Wednesday's Premier League home game against Wolves at Stamford Bridge after being given dispensation to do so under the government's elite sportspeople rules regarding the coronavirus.
The 47-year-old will be allowed to join Chelsea's bubble but must then quarantine for five days when not at the training ground or the stadium.
Sources told ESPN that Tuchel was hoping to wait until the end of the season to decide his next move but was convinced to take over at Chelsea following discussions with director Marina Granovskaia and agent Pini Zahavi.
The move comes after Chelsea beat Luton Town 3-1 in Sunday's FA Cup fourth-round clash at Stamford Bridge but following a serious downturn in Premier League form, losing five of their past eight games.
ESPN reported recently that Chelsea were torn over the future direction of the club, having become frustrated with a lack of progress under Lampard despite spending £220 million in the summer transfer window.
Chelsea had approached former RB Leipzig coach Ralf Rangnick to take the job on a temporary basis, but he ruled himself out of the running. They also sounded out Leipzig coach Julian Nagelsmann over whether he would be prepared to leave the club mid-season, but sources have confirmed that he also dismissed Chelsea's interest.
Sources have told ESPN that Tuchel sounded out another Premier League club on Saturday to seek their assessment on Chelsea as he mulled over whether to enter advanced talks.
His subsequent decision to pursue an agreement has led to Lampard's departure, bringing to an end his 19-month tenure in charge of a club he spent 13 years with as a player.
Lampard, 42, leaves Chelsea ninth in the Premier League, 11 points behind leaders Manchester United having been appointed in July 2019. He succeeded Maurizio Sarri and inherited a team reeling from the loss of talisman Eden Hazard to Real Madrid and a FIFA transfer ban that rendered the club unable to buy players during his first transfer window at the helm.
That ban was reduced on appeal, which meant Chelsea could spend in January 2020 but opted not to do so, with Lampard bringing through several young players including Mason Mount, Fikayo Tomori and Tammy Abraham.
Chelsea were outclassed by Bayern Munich at the Champions League round-of-16 stage but secured qualification for the following season's competition on the final day of the Premier League campaign by finishing in fourth place.
Chelsea went top of the Premier League on Dec. 5 as part of a 17-game unbeaten run in all competitions, but their form nosedived thereafter, losing to Everton, Wolverhampton Wanderers, Arsenal, Manchester City and Leicester City in the space of five and a half weeks.
ESPN reported last week that several players had become confused by Lampard's ever-changing team selection and disillusioned by his tactical approach.
Chelsea were also keen to find a German-speaking coach to get the best out two of their most expensive summer signings, Kai Havertz and Timo Werner, who have both underperformed since arriving for £71m from Bayer Leverkusen and £47m from Leipzig, respectively, in the summer.
Information from ESPN's France correspondent Julien Laurens and senior writer Mark Ogden was included in this report