Several players will decide the success of the Oklahoma Sooners this fall.

Some Sooners will have more of an impact than others and will be counted on to be the foundation of the 2014 squad. Last week we counted down the most important players on offense with quarterback Trevor Knight atop the list.

This week, we’ll count down the five most important players on defense, taking into account their expected contribution, the quality of their backups and their previous production. We begin the countdown with No. 5.

No. 5: CB Zack Sanchez, sophomore

2013 role: Sanchez was arguably the biggest surprise on the roster. He went from post-spring afterthought to freshman All-American. Sanchez finished among the league leaders with 15 passes defensed and stabilized the cornerback spot opposite eventual NFL fourth-round pick Aaron Colvin.

Expected 2014 role: Sanchez will play a critical role, both as an anchor in the secondary and a leader in the meeting room. He continued to improve and develop this spring with an eye on becoming a shutdown cornerback in the mold of Colvin. But Sanchez’s biggest impact could come off the field as he has to take a leadership role with several inexperienced players battling to start at the other cornerback spot.

Why he’s important: His presence and mental approach should help the entire secondary. He brings experience as a player who has started all 13 games he’s played in crimson and cream, yet he also brings youth and upside as a player who still has room to grow. Sanchez should be one of the top playmakers on the Sooners’ defense in 2014.

If he was missing: The Sooners wouldn’t have an experienced cornerback on the roster. The coaches will lean on Sanchez to bring them peace of mind as a returning starter, but he’s also hungry to grow into one of the conference’s top cover men. Without him, the Sooners would have a significant weakness in a defense that should be among the Big 12’s best.