Baltimore Ravens defensive lineman Haloti Ngata has been suspended for the remainder of the regular season by the NFL for violating the league’s policy on performance-enhancing substances.

The league does not release the details of the failed test that triggered the suspension, but Ngata said he took Adderall, which requires a prescription on record with the NFL because it is on the league’s banned substances list.

“I made a mistake, and I own this. I took Adderall and take full responsibility for doing this,” Ngata said in a statement released by the Ravens. “I am deeply sorry and broken up over this. I let down my family, my teammates, Ravens fans and myself. My hope is that the Ravens make the playoffs, and I believe they can do this. And, then I can come back and help us win.”

The Ravens (7-5) play at Miami on Sunday and have a difficult road to the postseason in a packed playoff race in the AFC.

“This is disappointing news for the Ravens. We are disappointed with Haloti, but no more than he is with himself,” general manager Ozzie Newsome said.

Ngata is eligible to return to the roster Dec. 29, the day after the regular season ends. He will be available for the playoffs should the Ravens qualify.