Maroney declared for the 2006 NFL Draft after the completion of his junior season at the University of Minnesota and was selected in the first round with the 21st overall pick by the New England Patriots. He was the second running back selected behind Reggie Bush. While splitting time with fellow running back Corey Dillon in 2006, Maroney was part of what coach Bill Belichick called the best running back corps he had ever coached.