Sillah is 19 years old and comes from Gambia. He was with Olympiakos for only a year before joining Forest.
Forest's Head of Football Development & Talent Management, Craig Mulholland, said that it's essential to have a mix of local and international players in the club's emerging talent pool.
He believes Sillah has high potential and is excited to have added a skilled goal-scorer to the young squad.
Mulholland also mentioned that Sillah is eager to improve and is looking forward to seeing how he adapts to the club.