Montee Ball said there's no such thing as pass protection for running backs in high school. In college he was merely introduced to it. The Denver Broncos' rookie running back has quickly learned that at the NFL level taking on pass rushers is nearly as important as carrying the ball. "My problem is I'm coming from Wisconsin a power school and I had 900 carries in four years. Whenever I was out on the field I was getting the ball a majority of the time" Ball told FOX Sports this week. "But with this offense and No. 18..." Ball didn't finish that sentence with words. Just an exhale. That said it all. As the Broncos prepare for Thursday's NFL regular-season opener against the defending Super Bowl champion Baltimore Ravens it's clear one of the big keys to their offense will be the play of their running backs following the departure of Willis McGahee. The wide receivers and linemen have had success at this level before. And "No. 18" - Peyton Manning - figures to be even better this season after one year of getting acclimated to his new surroundings and getting healthier. But in the backfield it's a rookie (Ball) a second-year player trying to prove he's not fumble-prone (Ronnie Hillman) and a veteran trying to show he can run and stay healthy (Knowshon Moreno).