The 21-year-old, who previously featured for Macclesfield in England, had been playing in the third tier of the American system after a failed spell at LA Galaxy
The 21-year-old had been playing with Orlando City in the third tier of football in the United States, after previously moving to LA Galaxy in 2011.
The deal is subject to clearance from the Football League, after being initially delayed due to a wrangle in his contract with the Florida-based outfit.
It had been thought that his contract in Orlando was valid after the end of the summer transfer window, which would have rendered Rooney unable to sign for a European club until January 1.
However, the deal looks set to go ahead, with Rooney's contract running until the end of the season.