The Philadelphia 76ers have experienced some roster changes as they look to build a roster that can reach the mountaintop in the NBA. The Sixers have been busy throughout the summer with a roster upheaval led by new President of Basketball Operations Mike Gansey and the front office.The Sixers lost Andre Drummond to the New York Knicks in free agency on Friday night. He served a role in Philadelphia both on the court and as a great locker room guy for the youngsters. He averaged 6.4 points and 8.4 rebounds off the bench and even developed a 3-point shot, which is impressive this late in his career.As Drummond moves on to the Knicks, he took to Instagram to give a heartfelt goodbye to the Sixers and the city of Philadelphia after two seasons with the team.View this post on Instagram