Tillman is training to become an FBI agent, according to two law enforcement sources.
Tillman spent 12 seasons with the Bears and finished out his NFL career helping the Carolina Panthers make it to Super Bowl 50 last year. Now, he will have his mettle tested during the FBI's 20-week training program in Quantico, Virginia.
His FBI training was first reported by The Chicago Tribune
. Tillman declined to respond to CNN's request for comment.
At 36 years old, Tillman is nearing the end of the fourth quarter when it comes to the FBI's age limit for trainees. New special agents must be appointed before their 37th birthday. Tillman turns 37 in February.
The fact Tillman earned a degree in criminal justice at Louisiana-Lafayette before he was drafted by the Bears in 2003 will likely be helpful to him at the FBI Training Academy.
"Agent trainees study a broad range of subjects that grounds them in the fundamentals of law, ethics, behavioral science, investigative and intelligence techniques, interrogation and forensic science," according to the agency's website. "Students learn how to manage and run counterterrorism, counterintelligence, weapons of mass destruction, cyber and criminal investigations."
The popular athlete retired from the NFL last year and is known also for his philanthropy. He will spend more than 800 hours training in four major concentrations: academics, case exercises, firearms training and operational skills.
"Each special agent must have the knowledge, skills, commitment, and fortitude to investigate terrorists, spies, and a raft of dangerous criminals -- all while wielding their law enforcement powers with compassion for those they encounter and respect for the US Constitution and the laws they enforce," according to the FBI's website
Tillman, who earned star-athlete status with his unique talent for punching the football out of his opponent's clutches -- known as the "Peanut Punch" -- will soon earn a gold FBI badge, if he successfully makes it through the rigorous training academy.