Manchester City's disappointment that Benjamin Mendy will miss the rest of the season because of a knee injury was compounded yesterday, after the Premier League giants received news that Sergio Aguero was involved in a vehicle crash in Amsterdam on Thursday.
"Our first impression is that this will be a bit long, longer than what we imagined, which is a shame", said Guardiola after the victory of the Citizens against Donetsk in the champions League (2-0).
Losing the 23-year-old for the majority of the season will be a big blow to City as he is not only an excellent player, he's also their only natural left-back.
Given City's trip to Chelsea, questions may be asked why Aguero was in the Netherlands 48 hours before such a serious match.
Perhaps no one celebrated quite like Benjamin Mendy after Manchester City broke the deadlock at Stamford Bridge on Saturday.
Meanwhile, Chelsea head coach Antonio Conte said the hamstring injury sustained by striker Alvaro Morata in the first half was "not serious", although he is expected to miss worldwide duty with Spain.
City's £52million summer signing is out for seven months, but seemed happy enough in hospital - after he found a striking resemblance between the nurse pushing him and Stoke forward Jese Rodriguez.
Delph has been a peripheral figure since joining City from Villa in July 2015, but he has been recalled to the England squad for this month's final World Cup qualifiers, against Slovenia and Lithuania.
"We will see in January", the City boss added.
The last high-profile footballer to suffer an ACL injury was Manchester United striker Zlatan Ibrahimovic.