The 20-year old younger brother of Manchester United star Wayne joined the Red Bulls in January this year but has made just three appearances so far.
Yesterday, the former Macclesfield Town man scored the winner in the Red Bulls' come-from-behind 2-1 win over FC New York in the Lamar Hunt US Open Cup and feels things are finally beginning to settle for him after a tough start.
"It's a physical league. I thought it was going to be slower than what it was," Rooney said.
"And I watched it on TV; you can see it's a fast league. The way they play, it's pretty much the same as England. It's fast, it's physical.
"I think it's the same as the English league. I know that's one thing I need to work on, my pace. I just need to keep working hard and hopefully it turns out right for me."