The team announced Thursday that it has signed its third-round draft pick to a four-year contract.
The Cardinals did not disclose the financial terms of the deal with the defensive back, but NFL.com's Albert Breer reported it's a four-year, $3.052 million contract that comes with an initial signing bonus of $265,000. The balance of the $662,500 bonus is spread across Year 2, 3 and 4.
The only way Mathieu won't receive the full payment is if he's dismissed from the team for drug use.
"I never doubted it," Mathieu said of signing an NFL contract, via the Cardinals' team website. "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."
Mathieu was kicked off the LSU team for failing multiple drug tests, and SI.com's Peter King reported last month the Cardinals planned to protect themselves with regular drug tests and a contract that had no guaranteed money.
That didn't happen. Mathieu will be fairly compensated -- given he stays clean.
Follow Dan Hanzus on Twitter @DanHanzus.