Fall has already gathered a significant fan following and displayed potential that has the Celtics organization invested in his future.
"It's another opportunity to keep proving myself," Fall said. "I've worked really hard to get to this point. I'm really fortunate to be in this position, and I'm going to keep fighting to show I can play in the NBA and keep getting better."
The two-way contract move Sunday allows the Celtics to assign Fall to their G League affiliate in Maine, where they want him to play significant minutes and develop under new head coach Darren Erman.
"It's always better to be on the court than to be on the bench," Fall said of playing in the G League. "You don't get better not playing, you get better playing basketball. Like I said, that's an opportunity for me to keep playing, keep proving myself, keep improving a lot of areas I want to keep working on."
Boston had signed Fall to an Exhibit 10 contract after he had gone undrafted out of UCF. The two-way contract allows a player to make approximately $350,000 if his NBA team brings him up for the full 45-day allotment.
Fall averaged 10 points, 7.7 rebounds and 2.4 blocks in his four college seasons at UCF.
ESPN's Tim Bontemps contributed to this report.