Norway's team doctor believes Arsenal captain Martin Odegaard could be out of action for three weeks after picking up an ankle injury on international duty.
The Gunners midfielder was left clutching his left ankle on Monday night after an innocuous-looking tangle with Austria's Christoph Baumgartner on the hour mark of his side's 2-1 Nations League win in Oslo and was helped off the pitch in tears by team-mate Erling Haaland.
The 25-year-old has returned to London for further assessment by Arsenal's medical staff.
Gunners boss Mikel Arteta is already without Declan Rice for the north London derby at Tottenham on Sunday following the midfielder's red card in the draw against Brighton before the international break.
Summer signing Riccardo Calafiori is also a doubt after he was forced off during Italy's Nations League match against France with a calf problem and the defender returned early to start on his recovery with Arsenal.
While no official update on Odegaard was expected until Arteta spoke to the media ahead of the Spurs game, Norway's team doctor Ola Sand believed the former Real Madrid midfielder would need a few weeks of rehabilitation.
"Such ankle injuries often take at least three weeks. Anything other than that is just a bonus and then it can take longer," Sand told Norwegian newspaper VG.
"What we have so far obtained from the MRI examination in London is that there is probably no fracture in the ankle.
"It is always a bit difficult to interpret an MRI scan when you have had an old injury, but Arsenal are almost certain there is no breach, but this may still take some time.
"In the event of a fracture, we are talking about being out of action for six weeks plus."
Following Sunday's derby, Arsenal open their Champions League campaign away to Atalanta and meet title rivals Manchester City at the Etihad Stadium on September 22.
As well as missing Odegaard and sweating on Calafiori, fellow summer signing Mikel Merino is sidelined by a fractured shoulder suffered in his first training session.
Striker Gabriel Jesus, though, could soon be back in contention following a groin problem.
