He was ultimately selected by the Arizona Cardinals in the third round.
Upon being drafted, head coach Bruce Arians said Mathieu "will be assigned to the position of free safety," per ProFootballTalk.com.
Let's examine Mathieu at the free-safety spot and the other ways he could potentially be utilized as a rookie.
With only two interceptions in his two seasons at LSU, Mathieu wouldn't necessarily be considered a ballhawk by the conventional definition, but he's quicker than fast, and there's no doubting his electric return ability.
Therefore, allowing him to simply focus on tracking the football in flight and giving him a better opportunity to pick off passes from center field is logical.
At 5'9'' and 186 pounds, Mathieu definitely will be undersized for his new position, but a lack of height isn't nearly as important at the safety spot as it is at cornerback.
Mathieu will likely be given the freedom to roam the deep middle with intercepting the football is main responsibility.
In theory, this polarizing player could flourish as a play-making free safety. He'd be a prime candidate to take a few picks to the house in his rookie campaign.
Mathieu played cornerback in college, yet questions about a difficult transition to the NFL due to his size are warranted.
However, with spread offenses becoming more of the norm at the professional ranks, Mathieu could carve out a niche as a pesky, situational nickel corner to cover the smaller and speedier slot receivers.
He's a relatively stout run defender and has experience as a blitzer, two strengths that would be accentuated if he played closer to the line.
Mathieu could have trouble in coverage, but his propensity to create turnovers means the Cardinals coaches will find a way to get him on the field on defense.
Mathieu is magical with the ball in his hands, regardless of the situation. He was a dynamic punt returner for the Tigers in 2011, returning two kicks for touchdowns and nearly going the distance twice against the Georgia Bulldogs in that year's SEC title game.
The only problem?
Patrick Peterson stands in his way as Arizona's primary returner.
Mathieu's LSU teammate led the league with four punt-return touchdowns as a rookie, and although his return average decreased in 2012, he's considered one of the league's most dangerous in the open field.
If the Cardinals want to keep Peterson as fresh as possible for his traditional cornerback duties, there's a chance they give Mathieu a shot to field punts.
William Powell is the club's primary kick returner, and one has to expect Mathieu will compete for that job as well.
He could have more of an impact on special teams than he does on defense in his debut NFL season.
The Cardinals will use Mathieu however they see fit, and apparently, he'll start out at free safety. But bringing him into the box on occasion as well as using him as the nickel corner wouldn't be a bad idea.
While it's hard to advocate taking Peterson's return responsibilities away, most full-time defenders aren't full-time return men.
Tyrann Mathieu can undoubtedly help Arizona in a variety of ways.