The Magpies are looking to strengthen their midfield options with Sandro Tonali set to make the switch to Spurs in a £100 million pound move.
Newcastle have identified Stiller as the perfect replacement for Tonali, according to Bild.
The 25-year-old has been a midfield mainstay for Stuttgart. In 2025/26, he made 34 league appearances, scoring two goals while providing five assists as his side finished 4th in Bundesliga.
Stiller made a single appearance for Germany at this summer's World Cup, completing 45 minutes off the bench in the 2-1 group defeat against Ecuador.
With Newcastle set to make upwards of £200 million from the sales of Anthony Gordon to Barcelona and Tonali to Tottenham, they certainly aren't short of cash as they look to revamp their squad following their respective departures.
Stiller has two years left on his contract at Stuttgart, and Newcastle will likely have to fend off other top European sides for his signature.