Citing mostly unnamed sources, the Detroit Press on Friday (7/15) reported that rapper Eminem [ tickets ] could retire as a solo artist following his Sept. 17 concert in Dublin, Ireland.

Eminem--the best-selling artist in his genre's history--feels he's got nothing left to prove as a rapper, and is "trapped by musical expectations," according to the Free Press story.

Some of Eminem's business partners and members of his D12 crew told the newspaper that the 33-year-old rapper--whose real name is Marshall Mathers--would like to emulate mentor Dr. Dre, who has morphed from rapper to acclaimed producer as he entered his 30s.

"Em has definitely gotten to the level where he feels like he's accomplished everything he can accomplish in rap," Eminem's sidekick Proof told the newspaper. "He wants to kick back and get into the producing thing."

"Marshall is very smart about this stuff," an unnamed musical partner told the Free Press. "He knows the danger of being at this level, where there's nowhere to go but down."

Eminem's manager, Paul Rosenberg, told the newspaper that "no official decision" about the artist's future has been made.

The cover of "Encore," the 2004 Eminem album that may now be his last, shows the picture of the artist taking a bow.

"I was actually pretty shocked when no one picked up on the concept," Rosenberg said.

Eminem is currently on the road with 50 Cent and others with the Anger Management 3 Tour.