Belgian midfielder De Bruyne – who signed a new contract through to 2023 – insisted City are fine without the former Barcelona star.
"It doesn't matter," said De Bruyne. "We will still do what we need to do, with or without him.
"He chose United. Okay, there are a lot of good players. If they want to come, they want to come, and otherwise we will do it with our team."
City are 12 points clear of second-placed United atop the Premier League table after 24 matches.
Sanchez could make his debut for Jose Mourinho's side at Yeovil Town on Friday, ahead of the trip to Tottenham in the league midweek.
With the Chilean gone, Arsenal pulled off a win over Chelsea in the league cup semi-final that will see them face De Bruyne and City in the final in late February.