The Brazilian goalkeeper was forced off at half time of Sunday's 2-0 win over Nottingham Forest due to a shoulder issue.
Ederson appeared to sustain the injury in a challenge with Willy Boly, before receiving treatment from Man City's medical staff.
The 30-year-old managed to see out the remainder of the first half, but he was replaced at the break by his deputy Stefan Ortega.
Ortega kept Forest at bay as Erling Haaland came off the bench to double the advantage after Josko Gvardiol had opened the scoring in the first half.
Guardiola provides concerning update on Ederson
As a result of the 2-0 win, Man City finished the weekend in second place and just one point behind leaders Arsenal with a game in hand.
While the title fight remains in their hands, the Citizens appear to have major doubts over whether they will be able to call upon their first-choice goalkeeper for the run-in.
When asked about Ederson after the game, Guardiola told reporters: "It doesn't look good. We'll see tomorrow with the doctor."
Ederson will now have an anxious wait to establish whether the shoulder injury will keep him out of Man City's final three games against Wolverhampton Wanderers, Tottenham Hotspur and West Ham United.
Ortega ready to deputise once again
Ortega came off the bench on Sunday to feature as a substitute for the third time this season after previously doing so in January's win over Newcastle United and last month's win over Liverpool
The German shot-stopper followed his appearance against Liverpool with three consecutive starts due to an injury to Ederson.
Ortega has proven to be a more than capable deputy and will be waiting in the wings should Ederson be ruled out for the remainder of the campaign.
The 31-year-old, who arrived from Bochum in 2022, has kept seven clean sheets in 17 competitive appearances this season.