NFL.com's Ian Rapoport reported on "NFL Total Access" that Mathieu -- who signed a four-year contract with the Cardinals on Thursday -- already has entered the NFL's drug-testing program and could be subject to up to 10 tests per month, according to a source close to the situation.
Mathieu has welcomed all additional drug testing, agreeing to be tested once per week upon being drafted by the Cardinals. Because he's in the league's program, he'll have no choice.
Mathieu's agent, Pat Lawlor, told Rapoport that "both sides understood the issues we were dealing with."
Rapoport and Albert Breer reported earlier Thursday that Mathieu received a portion of his signing bonus up front, with the rest coming to him over the remaining three years -- granted he doesn't fail a drug test. Mathieu receives $265,000 initially, 35 percent of the normal slot for a 69th overall pick and less than any player has received up front in five years, according to Rapoport.
Mathieu's checkered past complicated the process, with the contract taking seven weeks to work out. The deal is not dissimilar to the rookie pacts signed by New England Patriots tight end Aaron Hernandez and St. Louis Rams cornerback Janoris Jenkins, two players who -- like Mathieu -- came out of college with red flags flapping in the wind.
Follow Dan Hanzus on Twitter @DanHanzus.