Maatsen pens new Chelsea deal before joining Dortmund — Romano

"Ian Maatsen signs new deal at Chelsea valid until June 2027, two year extension… and it will include a release clause! The clause will be valid starting from summer 2024," Fabrizio Romano tweeted.

"Maatsen will fly to Dortmund tonight to join Borussia on loan, medical tomorrow as [previously] revealed."

The 21-year-old's previous contract with Chelsea ran out until 2025. The new deal has been agreed to protect the Dutchman's value and avoid losing him on cheap.

The full-back has clocked 376 minutes of competitive football across 15 appearances across all competitions for Chelsea so far this season.