New signings
- Ailton Ferreira Silva (Sporting Clube de Braga, end of loan)
- Hamadi Al Ghaddioui (SSV Jahn Regensburg)
- Fabian Bredlow (1. FC Nürnberg)
- Marcin Kaminski (Fortuna Düsseldorf, end of loan)
- Atakan Karazor (Holstein Kiel)
- Philipp Klement (SC Paderborn 07)
- Mateo Klimowicz (Instituto AC Cordoba)
- Gregor Kobel (TSG Hoffenheim, on loan)
- Orel Mangala (Hamburger SV, end of loan)
- Roberto Massimo (Arminia Bielefeld, end of loan)
- Pascal Stenzel (SC Freiburg, on loan)
- Tanguy Coulibaly (FC Paris Saint-Germain)
- Maxime Awoudja (FC Bayern München)
- Sasa Kalajdzic (FC Admira Wacker Mödling)
- Luca Mack (VfB U19)
- David Grözinger (VfB U21)
- Nathaniel Phillips (Liverpool FC, on loan, August 2019)
- Wataru Endo (VV St. Truiden, on loan)
- Silas Wamangituka (Paris FC)
- Nikolas Nartey (1. FC Köln)
- Philipp Förster (SV Sandhausen)
- Ebenezer Ofori (New York City FC, end of loan, January 2020)
- Darko Churlinov (1. FC Köln)
- Nathaniel Phillips (Liverpool FC, on loan, January 2020)
- Clinton Mola (Chelsea FC)
Departures
- Christian Gentner (1. FC Union Berlin)
- Dennis Aogo (Hannover 96)
- Andreas Beck (KAS Eupen)
- Alexander Esswein (Hertha BSC, end of loan)
- Anto Grgic (FC Sion)
- Ozan Kabak (FC Schalke 04)
- Pablo Maffeo (FC Girona, on loan)
- Alexander Meyer (SSV Jahn Regensburg)
- Benjamin Pavard (FC Bayern München)
- Hans Nunoo Sarpei (SpVgg Greuther Fürth)
- Ron-Robert Zieler (Hannover 96)
- Steven Zuber (TSG Hoffenheim, end of loan)
- Ailton Ferreira Silva (FK Qarabag, on loan)
- Erik Thommy (Fortuna Düsseldorf, on loan)
- David Kopacz (Górnik Zabrze, on loan)
- Timo Baumgartl (PSV Eindhoven)
- Chadrac Akolo (SC Amiens)
- Nikolas Nartey (F.C. Hansa Rostock, on loan)
- Nathaniel Phillips (Liverpool FC, end of loan, December 2019)
- Santiago Ascacibar (Hertha BSC, January 2020)
- Emiliano Insua (Los Angeles Galaxy, January 2020)
- Ebenezer Ofori (AIK Solna, January 2020)