Liverpool are likely to be without Virgil van Dijk for the remainder of the season, meaning they will have to make do with just two established central defenders until January at the earliest. Fabinho, who deputised at centre-back, is yet to make his return from an injury of his own, while Thiago Alcantara and Alex Oxlade-Chamberlain both missed Sunday's trip to the Etihad.
The last thing they needed at City, then, was another injury, but because it's 2020, they got one anyway. There was real concern in the second half when Alexander-Arnold suddenly went down off the ball with half an hour to play, and he had to be helped off the pitch to be replaced by James Milner.
The prognosis could be worse, but various reports, including from The Times' Paul Joyce, say the 22-year-old is facing around four weeks on the sidelines. The Mail's Dominic King elaborates somewhat, saying that in addition to England's fixtures in the international break, Alexander-Arnold will miss Liverpool's fixtures with Leicester and Brighton, with the first possible return date coming against Wolves on 5th December.
He will also miss Champions League clashes with Atalanta and Ajax if that timeline is to be taken at face value.