Kansas City running back Larry Johnson runs for a gain against Houston. The rap group SBL posted a song - which it has since removed - allegedly performed by Johnson. The song contains profanity and attacks Chiefs general manager Carl Peterson.

Kansas City, Mo. ? The NFL said Friday it was investigating whether a foul-mouthed rap song on a MySpace Web page was the work of someone impersonating Kansas City Chiefs running back Larry Johnson.

The song, rapped in a voice similar to Johnson’s and peppered with references to the f- and n-words, blasts Chiefs president and general manager Carl Peterson – suggesting it was made during Johnson’s holdout before he signed a five-year contract extension worth a guaranteed $19 million and nearly $28 million in the first three years.

The lyrics include: “Carl Peterson, the GM’s running it. They see me, they want to treat me like I’m running it. I wouldn’t give a (expletive) if I’m not coming back. I’d rather play for another team because I’d rather be a running back.”

Johnson on Friday denied any involvement in the song and said he had asked NFL security officials to look into it.

“Basically, I’ve had ongoing problems with people impersonating me on MySpace pages. I’ve alerted the NFL security about the raps on the Internet that supposedly have been rapped by me which they are not. It’s in NFL security’s hands, and I’m pretty sure they’ll take care of it to the best of their ability.”

As Johnson walked away from reporters, one asked Johnson whether the song was his. “Nope,” he said.

Asked whether he thought the voice was Johnson’s, Chiefs head coach Herm Edwards said he doesn’t like rap music and had no plans to listen to the song.

James Tinberg, owner of Basement Entertainment, whose rap group SBL (Same Blood Line) Mob has the MySpace page where the song was hosted before it was taken down, at first told several Kansas City-area news organizations that Johnson was at a recent party where he rapped freestyle for about 10 minutes. That was edited into a three-and-a-half-minute song, Tinberg said, adding that music engineers and others who were editing lyrics at the party made Johnson “say funny stuff.”

“It wasn’t his words in order,” Tinberg told KSHB-TV. “It’s so simple to move it around, it’s just a couple of clicks. It’s like Photoshop with music.”

But Tinberg, 23, of Kansas City, later told the Associated Press that the rapper isn’t Johnson but someone imitating the athlete’s voice. He said he lied about the song to reporters and that he “used the media.”

Tinberg said the rap was done as a publicity stunt to promote his music label. The group SBL Mob has an album due out in December, and Tinberg said he thought publicity over Johnson’s alleged involvement would spark interest.

“That was never actually Larry Johnson,” Tinberg said in a phone interview. “It was never his voice. It was another dude who sounded like LJ.”