There was a time when pairing rookie running back with seemed like a no brainer; a way to diversify Denver's offense and take pre sure off the aging All-Pro. Three years later, Hakeem Olajuwon Jersey Ball is still buried on Denver's depth chart. With 175 rushing attempts in two seasons, he has yet to take off the way the team had hoped.During Denver's latest preseason game, he was e sentially the fourth-string running back."I was expecting a lot more playing time," Ball said, . "It caught me off guard. But my head's not down; I'm going to keep it up and keep fighting."It might be easy to forget that Ball, a second-round pick in the 2013 , was selected a few picks ahead of Green Bay's and hundreds of picks before , the undrafted running back who has overtaken Ball's spot on the ' depth chart.And while this doesn't seem to matter now -- so long as Denver has a capable option behind Manning, they'll be fine -- remember a year ago when Manning was injured and desperate for a running game to pick up the slack.That takes more than one all-around power back. Malcolm Miller Jersey