Sergio Aguero has announced he is self-isolating after testing positive for coronavirus.
The Manchester City striker had been self-isolating after being identified as a close contact of another confirmed case.
Now the 32-year-old has revealed he too has tested positive.
The Argentine tweeted: "After a close contact, I've been self-isolating and the latest test I took was positive for Covid-19.
After a close contact, I've been self-isolating and the latest test I took was positive for COVID 19. I had some symptoms and I'm following doctor's orders for recovery. Take care, everyone!— Sergio Kun Aguero (@aguerosergiokun) January 21, 2021
"I had some symptoms and I'm following doctor's orders for recovery. Take care, everyone!"
It is yet another setback for City's record goalscorer, who has started just three matches this season.
Aguero missed the end of last term and the start of the current campaign after undergoing knee surgery in June.
His return to action was then complicated by a hamstring injury in October and he later experienced further discomfort in his knee.
After a series of substitute appearances he had been due to return to the starting line-up in City's FA Cup third-round tie against Birmingham earlier this month but was then told to isolate.
He has been unavailable for the last four games for this reason and the latest news means he will be out of action a while longer yet.
He is one of a number of positive coronavirus cases at City since Christmas. Kyle Walker, Gabriel Jesus, Ederson and Ferran Torres are among the senior players also to have been forced to isolate in recent weeks.
Man City made it nine wins in a row by beating Aston Villa. They're on a roll - and have a favourable fixture list ahead of the crunch clash with Liverpool, writes Sky Sports' Peter Smith...
Nine wins in a row. Aston Villa gave Manchester City more of a fright than any other side during that run but the streak goes on.
Dean Smith felt the result could easily have gone the other way - and but for a bigger deflection here, a cuter pass there, and the interpretation of a key offside call, City's charge could have stalled in the pouring rain at the Etihad on Wednesday night.
But once again, they found a way to win.
That defence - which has conceded just two goals in those nine victories across all competitions - racked up another clean sheet, with John Stones and Ruben Dias once again superb.
In attack, Kevin De Bruyne's injury didn't stop the flow of the City attacks, with 28 shots unleashed as Bernardo Silva broke the deadlock and Ilkay Gundogan sealed it with a late penalty.
We've seen Guardiola's City teams go on runs like this before - and it has proven to be an ominous sign for the opposition.
City were down in 12th when they last lost, going down 2-0 to Tottenham in November. They finish Wednesday second to Manchester United in the Premier League table but knowing their game in hand would take them top. It's some turn around - and it is going to take something special to stop this roll they're on.
Inevitably, eyes are drawn to February 7, when City go to Anfield.
Before facing Villa, Guardiola spoke about the relentless nature of the fixture list this season and the quick turnaround between matches - but he will surely have that game against Jurgen Klopp's side in his thoughts.
- Man City 2-0 Aston Villa - Match report and highlights
- How the teams lined up | Match stats
- Premier League table | Top scorers | Results | Fixtures
In two and a half weeks' time, City will head to the home of the defending champions needing to strike a crucial blow in the title race.
Unlike the previous three seasons, Liverpool aren't the only other side in the running, and there are a series of tough tests coming on the heels of that clash with the Reds - but a big performance at Anfield would be some statement from City.
Before then, they have four matches, including three in the Premier League, which they will be heavy favourites to win.
That doesn't mean they will - there is a growing list of upsets in this unpredictable season - but there is a strong chance City will go to Merseyside with even more momentum to their charge, and growing confidence in their title ambitions.
Cheltenham away in the FA Cup on Saturday will be an opportunity to rotate and give the likes of De Bruyne and Kyle Walker, who also went off against Aston Villa, time to recover.
West Brom held City to a draw earlier this season but Guardiola's side are a different beast now and should win at the Hawthorns next Tuesday.
Basement club Sheffield United are next up the following Saturday, before fourth-bottom Burnley the Wednesday ahead of the Liverpool match.
City could hardly ask for a more favourable run-in to their pivotal encounter with Klopp's side.
Opportunities to extend the winning run, opportunities to ease De Bruyne, Walker, Nathan Ake, Aymeric Laporte and the isolating Sergio Aguero back to fitness, and opportunities to put the pressure on United, Liverpool, Leicester, and the other sides trying to keep pace at the top.
They could quite possibly have built up a daunting 20-game unbeaten streak by kick-off on February 7.
In contrast, Liverpool's own build-up to facing City includes a FA Cup game with Manchester United, followed by Premier League games away to Tottenham and West Ham, before a home match with Brighton on the Wednesday before hosting Guardiola's side. It's a tricky fortnight.
As this Premier League season tips into its second half the stakes are rising: the slip-ups will become more costly, the winning runs more important.
City are on a roll and have the opportunity to capitalise…