The midfielder had to be helped off the pitch and boarded his flight back from Norway with the help of crutches.
Norway doctor Ola Sand spoke to Norwegian newspaper Verdens Gang about the scan which revealed that the Arsenal captain has likely avoided fracturing his ankle.
"What we have so far obtained from the MRI examination in London is that there is probably no fracture in the ankle,” Sand said.
“Such ankle injuries often take at least three weeks. Anything other than that is just a bonus. And then it can take longer.
“Both Stale (Solbakken) and I know that that collection hangs in the balance. It is not excluded. But we have to wait and see both what the MRI images show and how quickly he responds to treatment.
“Ankle injuries are very painful right away. With Martin, it was extremely painful. He became very worried.
“They are studying the MRI images now, and have sent them on. In the event of a fracture, we are talking about being out of action for six weeks plus.”
This means Odegaard will miss vital games against Tottenham, Manchester City, Atalanta and many more.
Arsenal will miss Declan Rice against Spurs due to suspension and already have Mikel Merino, Riccardo Calafiori, Gabriel Jesus and Takehiro Tomiyasu out in the medical room ahead of the North London derby.