Mathieu, a Heisman Trophy finalist as a sophomore in 2011 while playing alongside Patrick Peterson in the LSU secondary, was dismissed from the team the following offseason and reportedly admitted to teams during the NFL draft process that he failed upwards of 10 drug tests while in college. After initially announcing his intent to transfer, Mathieu instead sat out the 2012 season and declared for the draft.
The undersized 5-foot-9, 179-pound cornerback, whom some analysts believe will be a nickelback or free safety in the NFL, became a household name during LSU's run to the national title game in 2011, posting two interceptions, 11 forced fumbles, eight fumble recoveries, a team-leading 76 tackles, 7.5 tackles for loss, and 1.5 sacks. He also returned two punts for touchdowns and finished fourth national with a 15.6-yard punt-return average. In the process, he won the Bednarik Award as the best defensive player in the country, was a unanimous first-team All-American and finished third in the Heisman voting.
The 20-year-old trained with Peterson, his new teammate, in Louisiana last offseason, and Peterson's presence in Arizona had led to speculation that the Cardinals would be willing to take a chance on a player deemed by some experts to be a first-round talent.
While Peterson is entrenched at one starting position, the Cardinals lack certainty in the secondary after experiencing significant turnover this offseason. Jerraud Powers is expected to start at the opposite corner spot after being signed as a free agent from the Colts, and 2012 third-round pick Jamell Fleming and free-agent signee Antoine Cason also will provide competition. At safety, the Cards will have two new starters in Rashad Johnson, who replaces veteran Adrian Wilson, and Yeremiah Bell, signed from the Jets to replace free agent Kerry Rhodes.