The striker was withdrawn in the 67th minute after appearing to suffer an injury, with Crystal Palace forward Jorgen Strand Larsen replacing him.
The score was 1-1 when Haaland left the pitch, after Kristoffer Ajer had given Norway the lead and Joao Cancelo equalised before half-time.
Goncalo Ramos then completed Portugal's comeback less than 10 minutes after Haaland's departure.
The incident adds to a difficult international break for Manchester City, who have already lost Nico O'Reilly to injury while on England duty.
Rico Lewis was promoted from the Under-21s to replace O'Reilly in Thomas Tuchel's squad.
City will be particularly anxious over Haaland given his importance to Enzo Maresca's side this season. The 26-year-old has scored five goals in his first five Premier League appearances.
Manchester City are also dealing with uncertainty away from the pitch after being found guilty of more than 100 of the 130 charges brought against them by the Premier League.
The club strongly maintain their innocence and have launched an appeal against the verdict, with their sanction still to be determined.
Haaland's condition will therefore be closely monitored ahead of City's return to club football next weekend.
The Etihad side are due to face Liverpool on Sunday in their first match since the guilty verdict, making the striker's fitness an especially important concern.