Rangnick led Hoffenheim from the third tier of German football into the top flight in consecutive seasons before leaving in early 2011.
He is now director of sport at Salzburg but continues to follow the progress of his former team and believes relegation, which is looking increasingly likely, could be a blessing in disguise.
"Relegation would be a chance to get back to the roots because Hoffenheim was always a club who were successful with the philosophy of working above all with young players," he said.
"Sadly they have veered off this path recently."
Hoffenheim slipped 11 points adrift of safety after losing to Bayern Munich last weekend, and with just 10 games of the season to go, they are running out of time to save their season.
"The situation is unfortunately so dramatic that Hoffenheim risk going down automatically," Rangnick said in the Bild newspaper.
"To be honest, (the situation) really hurts me."