SOUTH BEND, Ind. - Brian Kelly has had to make big quarterback decisions several times in his career, but he admitted that last week's switch from Brandon Wimbush to Ian Book was the toughest yet, given their undefeated record.

However, the quarterback play is just one focus for Kelly as his team prepares for a top-10 matchup with Stanford. Hear what he believes are the biggest factors in capturing a win against the Cardinal.