Pat Lawlor, a Florida-based agent, said Friday that he became Mathieu's agent earlier this week. Mathieu released a statement Thursday saying he planned to enter the NFL draft and by hiring an agent he forfeits his final two years of NCAA eligibility, though Lawlor said Mathieu won't be eligible to file paperwork with the league until January.
Mathieu, a Heisman Trophy finalist a year ago, was kicked off the LSU team Aug. 10 reportedly for failing multiple drug tests.
"He just wants to start training," Lawlor said. "He didn't want to distract from LSU's bowl preparations. With there being some down time right now he thought it was the best time to make the announcement.
"It was crystal clear to him that he could not return if he hired an agent and he understood that and was fine with it. He's moving forward."
Lawlor said Mathieu was en route Friday to Boca Raton, Fla., where he will be training with Patrick Peterson Sr. at Florida Atlantic University.
Mathieu is continuing with his drug rehabilitation, but is no longer working with Houston-based John Lucas, a former NBA player, according to Lawlor.