Carter said it was a matter of protecting himself from players at a different position, such as linebacker.
"I'd tell one of them guards, 'Hey man, this dude is after me, man' " Carter said, citing one time when Romanowski was with Denver and Carter with Minnesota.
"Bill Romanowski - he told me he was going to take me out before the game, warmups. No problem. [He said,] 'I'm gonna end your career, Carter.' No problem. I put a little change on his head before the game. Protect myself. Protect my family. That's the league that I grew up in."
In other NFL news:
* Former NFL quarterback Ryan Leaf pleaded guilty to charges that he broke into a Montana home and illegally possessed painkillers, part of a deal with prosecutors that recommends he spend 9 months in a secure drug treatment facility. Sentencing was set for June 19.
* The NFL is telling retirees about a medical study that says former players live longer than men in the general population. The study by the National Institute for Occupational Safety and Health found 334 deceased men in a sampling of 3,439 former NFL players. Estimates for the general population anticipated 625 deaths.
* The Missouri attorney general will release details next week on how the St. Louis Rams want to renovate the Edward Jones Dome despite the team's desire to keep the plan secret.