After the 4-2 defeat at home to the Netherlands on Friday night, second-place Germany are three points behind Northern Ireland and three ahead of the Dutch, while Ronald Koeman’s side have a game in hand.
Gundogan had been expected to start, with Germany likely to return to a four-at-the-back system following a disappointing showing against the Netherlands. Bayer Leverkusen’s 20-year-old star Kai Havertz could be the man to take his place in the starting XI.
With four wins from their first four games, Michael O’Neill’s Green and White Army are surprise incumbents at the top of Group C, though they have yet to face either of the group’s heavyweight teams.
The countries most recently met in qualifying for the 2018 World Cup, with Germany recording a seventh straight wins against the Irish. Northern Ireland’s last win over Germany came courtesy of Norman Whiteside, way back in 1983.
Now, though, the onus is on Germany to put in a performance befitting one of the world’s best teams, as they have struggled for consistency following their humiliating early exit from last year’s World Cup.
The experienced presence of Gundogan in midfield will be missed, though his absence could prove to be a blessing in disguise if Havertz is given the opportunity to impress. He scored 20 goals in all competitions for Leverkusen last year and has two already this season, but is yet to record his maiden strike for his country.
If Gundogan doesn’t recover quickly from his illness, it could also cause a temporary headache for City boss Pep Guardiola.
With City rocked by the long-term injury to key defender Aymeric Laporte, Guardiola could now be left short of options in holding midfield, as Fernandinho is expected to fill in at the back.
Record signing Rodri should keep his place for the trip to Norwich on Saturday, but with Champions League and Carabao Cup games to contend with, City could see their squad stretched again if players aren’t at peak fitness.