Detroit Lions head coach Jim Caldwell said he believes RB Zach Zenner can be an effective option for the Lions this season because of his skill set and his steady improvement. ‘He can run the ball. He can pass protect. He can catch the ball out of the backfield if need be and I think just another year under his belt is going to be a great help. Zach is one of those guys that I think without question can be effective for us,’ Caldwell said.