The person spoke to the AP on condition of anonymity Mondaybecause he wasn't authorized to discuss the application. Hardy's agent, Drew Rosenhaus, didn't immediately return a phone message.
Hardy, who was arrested on a cocaine possession charge in a Dallas suburb in September, didn't play last season after a tumultuous 2015 with the Cowboys. Hardy began that season by serving a four-game suspension for his role in a domestic violence case in North Carolina.
Hardy, 28, would not receive a salary for playing in the Spring League, which is designed to give former NFL draft picks a shot to display their talent. The league isn't affiliated with the NFL, but NFL teams plan to send scouts to games and workouts.
Hardy had 15 sacks for the Carolina Panthers in 2013, when he was picked for the Pro Bowl.
He had six sacks in 12 games during his only season with Dallas. Cowboys owner and general manager Jerry Jones didn't re-sign him after initially saying he wanted to give Hardy a long-term deal.
Hardy was convicted by a judge in the North Carolina case, but prosecutors dropped the case in February 2015, during Hardy's appeal, because his ex-girlfriend couldn't be located to testify. Prosecutors said they believed Hardy and the woman had reached a settlement.
In November 2015, graphic photos were released of his bruised ex-girlfriend. The photos were taken within 24 hours of when Hardy was arrested in May 2014.
Spring League officials have extended invitations to a number of former NFL players, including QBJohnny Manziel and RBRay Rice. Other former NFL players have already signed up, including 33-year-old tight end Kellen Winslow.
The Spring League consists of four teams composed of free agents. The teams start training April 5 at The Greenbrier Resort in West Virginia and will play a total of six games there in a three-week span.