Spring practice is just over the horizon for Oklahoma. The Sooners defense could develop into the Big 12’s best in 2014. It won’t reach those heights without replacing two-time All-Big 12 cornerback Aaron Colvin.

Here's a look at the battle to replace Colvin:

Departed (2013 stats): Colvin was fifth on the team with 55 tackles in 2013. He added three pass breakups, one sack, one interception and one fumble recovery. His competitive nature and leadership example will be missed.

Spring contenders: Sophomore Stanvon Taylor; sophomore Dakota Austin; junior Cortez Johnson.

Summer contenders: Freshman Tito Windham; freshman Jordan Thomas.

The skinny: The Sooners won’t be able to replace Colvin, who was the best player in the secondary for the past three seasons.

Nonetheless OU needs someone to step up at the cornerback position opposite Zack Sanchez, a FWAA Freshman All-American who started all 13 games in 2013. Defensive coordinator Mike Stoops depends heavily on his defensive backs to be able to hold up in man coverage so he can come up with creative ways to terrorize opposing quarterbacks. That game plan falls apart if there’s a weak link in the secondary that is consistently being exposed.

Taylor, who started one game as a true freshman, spent the 2013 season as Colvin’s protégé, watching in the background while preparing to slide into his spot in 2014. That won’t happen if Taylor doesn’t take his game to another level, beginning this spring. The starting spot is there for the taking, but he’ll have to earn it with several other talented cornerbacks on campus.

Johnson, who started against Kansas State and Iowa State in Colvin’s absence, would bring an upgrade in size at the cornerback spot. At 6-foot-2, 201 pounds, he brings a physical presence that is unmatched by any of the other competitors.

Austin could be the most competitive of the contenders, but his lack of size (5-11, 151) is a major concern. The sophomore will be able to hold up in man-to-man coverage, but he’ll have to prove he can overcome his size limitations and play like he’s twice his size if he hopes to earn the starting spot.

Windham and Thomas arrive in the summer and could throw themselves into the competition as true freshman. Taylor and Austin escaped redshirt seasons in 2013 so there’s no reason to think Windham and Thomas can’t battle for immediate playing time.

Prediction: Don’t be surprised if there is some shuffling among some of the returning players in the secondary to help fill this void. If not, Johnson emerges as the front runner after spring. He passed Taylor on the depth chart during the 2013 season, so unless Taylor takes his game to another level, Johnson will emerge atop the depth chart. But, with two talented freshmen on the way, the lone certainty is that this battle will wage on deep into August.