The NFL tells TMZ Sports the league is looking into claims of domestic violence against line judge Carl Johnson.
We broke the story ... a woman claiming to be Johnson's former live-in girlfriend filed court documents and went to police claiming Johnson physically abused her in 2016 and 2017.
The woman tells TMZ Sports she also went to the NFL back in March 2017 asking for counseling.
An NFL spokesperson tells us, "The matter is under review under the league's personal conduct policy."
The PCP not only applies to players -- but ALL league personnel including coaches, owners and officials.
Johnson has denied the allegations in court -- but had no comment on the matter when contacted by TMZ Sports.