Mathieu said he knew signing a contract with an NFL team would be a process, but that he always knew it would happen, according to the team's official site.
"I never doubted it," Mathieu said of getting the chance to sign an NFL contract. "I knew it was a long shot and it would be a process, but to finally sit down and sign my name on the dotted line means a lot to me."
According to Schefter, Mathieu received a smaller signing bonus than he was slated for. Instead of the $662,500 he was supposed to get, the Cardinals gave him $265,000, which was likely a discount based on Mathieu's past.
Mathieu, considered by many to be a first-round talent, fell to the third round thanks to a shady history that included several failed drug tests and the dismissal from LSU's football team. Mathieu entered the 2013 draft without playing football in 2012, attending to drug rehab instead.
The Cardinals decided the pick was worth the risk of selecting Mathieu and took him 69th overall. Mathieu should have an immediate impact on the team's secondary, where he'll be paired with Patrick Peterson, which should help keep the team's fifth-ranked pass defense near the top of the league.