Ryan Williams signed a two-year with the Reds on July 26th, 2015, with the club having an option for a third year.
The forward teamed up with Barnsley after an undisclosed fee was agreed with Fulham.
Quick, agile and skilful, Williams enjoyed a successful six-appearance stint on loan at Oakwell last year.
The 21-year-old is an Australian youth international and has had Football League experience on loan with the Reds and at Oxford United.
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