A screenshot of the now-deleted Instagram post was uploaded on X, formerly Twitter, on Friday evening.
The caption of Hall's post read: "After 12 amazing years with this club, I just want to say thank you to everyone [at Chelsea]. Growing up through the academy, I always aspired to play for the first team, and I'm so proud to have been able to do so... To the staff and players of both the academy and the first team, thank you for helping me develop into the person I am today."
He added at the end: "Chelsea will always have a special place in my heart."