Kompany is close a comeback after recovering from a groin and thigh operation.
The Belgium crock broke down in May with the latest in a long list of setbacks that forced him to miss Euro 2016.
But Guardiola admits he faces a fight to win back his place considering the strong competition for places at the back.
New £50m signing John Stones has settled in well, while Nicolas Otamendi has raised his game following the arrival of Guardiola this summer.
“They have to compete with each other, we’ll see on the pitch what is the best for that game,” he said.