The 22-year-old, who joined the Magpies' Academy in the summer of 2018 from West Ham United, made 73 appearances for Newcastle's second-string during a four-year stint on Tyneside.
He was also part of the under-23s squad which reached the Premier League 2 Division Two play-off final and Premier League Cup final during the 2018/19 campaign.
Newcastle United Academy Manager, Steve Harper, said: "Rosaire has reached the age where he needs to be playing first-team football and we're happy to have helped him get the opportunity to do so.
"We’d like to thank Ros for his contribution since his arrival at the club and wish him all the best in the future. Good luck, Ros!”