The 18-year-old has completed a loan move to Austrian club TSV Hartberg this week.
Hartberg were fifth in the Austrian Bundesliga last season and will be bolstered by Osborne’s arrival.
Hartberg head coach Markus Schopp, a former Austria international, said: "Charlie was already with us in the spring and showed off his talent.
“He is a super exciting player who now wants to make his way into adult football.
“We will support him in this. He has very good abilities with which he can definitely help us."
Midfielder Osborne added: “I'm really happy to be here.
“I hope to gain important experience with the first team and get as many minutes of play as possible.
“I'm developing as a player and I definitely want to return after my loan in Hartberg as a better player than I am now.”