Sancho has been linked with United.
Sancho has a contract until 2022, so there is no pressure on Dortmund to sell, and they would surely only do so for a transfer fee nearing £100m.
But DC United star Rooney told BILD: "Dortmund is a great club with great fans, they trust their young players and you can see that in Sancho and the progress he has made in the last 12 months.
"Now Jadon has to ask himself whether he would get the playing time he gets in Dortmund when he moves to England, or would he just sit on the bench? Playing time is so important for a young player like Jadon, so if he gets the most playing time in Dortmund, he should stay there."