The 25-year-old has been impressive for Dortmund since joining the club from Freiburg in 2022, making 128 appearances, scoring six goals and providing 16 assists.
According to Sport Bild, the German giants want to tie Schlotterbeck down to a new long-term that will run until 2030, with his current deal ending in 2027.
Chelsea are currently suffering from a defensive injury crisis which forced Enzo Maresca to start 19-year-old Josh Acheampong alongside Benoit Badiashile in the 2-1 win against Liverpool recently.
Maresca is reportedly considering signing the Germany international defender whose contract renewal situation is also being monitored by Bayern Munich and Real Madrid.
"Playing internationally is what defines the club," said Schlotterbeck to Sky Germany earlier this year.
"Because it's become a habit over the years. But I also have to examine what I've done to ensure that we're not in a position where we're talking about the top four (in the Bundesliga). I want to play internationally, preferably with BVB."
Schlotterbeck is set to make his return to the national team this October after having missed months of action due to a meniscus tear in April that led to the centre-back missing the 2025 Club World Cup.
Nigeria international Samuel Chukwueze has expressed his excitement at rediscovering top form at Fulham, crediting manager Marco Silva for playing a crucial role in his resurgence.
Saturday proved to be a goal-fest in the Bundesliga as the top two sides in the standings blew away their opposition to pull further away from the rest.
Leeds completed a stunning comeback from 2-0 down to snatch a 3-3 draw against a reeling Liverpool and pile fresh misery on Arne Slot.
Manchester City secured a second successive Premier League victory at home against Sunderland, Chelsea were held scoreless away to Bournemouth while Tottenham managed to beat Brentford.
