City confirmed the change in the first period, with Riyad Mahrez introduced into the game for the Belgium international:
The nature of the injury was not initially clear, as De Bruyne didn't appear to pick up the problem in a challenge, although the Manchester Evening News reported it's a hamstring issue:
After the game, which City eventually won 1-0 thanks to Mahrez's goal, the player tried to ease fears that he was set for another long time out:
However, manager Pep Guardiola told reporters the talented playmaker could be out "a while."
He has already missed a significant portion of the 2018-19 campaign for his club because of a pair of injury issues.
In August, he picked up a knee ligament tear that sidelined him until October. However, upon his return, the former Wolfsburg and Chelsea man had another issue, prompting a further couple of months out of action.
As a result, De Bruyne has been limited to six Premier League starts this season.
Despite the Belgian's absence, the Premier League champions have thrived under manager Pep Guardiola.
Before the match with the Cherries, they were a point behind league leaders Liverpool; City also won the Carabao Cup last weekend and remain in contention for both FA Cup and UEFA Champions League glory.
While City have so many quality performers to call upon in midfield, few can replicate De Bruyne's influence when he's at full tilt. He is dynamic and direct on the ball, while his technical ability is among the best in the game, as he can find incisive passes in the final third and score himself.
City's ability to cope without De Bruyne has already been impressive this season, with Bernardo Silva and David Silva excelling. Ilkay Gundogan and Phil Foden are other fine alternatives in the central-midfield berths.