Former Broncos lineman John Moffitt announced his NFL retirement to his followers on the social media website twitter.

In the message, he offered a brief joke directed at the NFL's commissioner.

"Football was fun but my head hurts-haha kidding roger goodell," he wrote. "I'm on to new things, thanks to everyone along the way!!!"

The Associated Press got a hold of Moffitt, who told the wire service that he did not quit over a dispute of playing time, which was initially reported.

"I just really thought about it and decided I'm not happy. I'm not happy at all," Moffitt told the AP. "And I think it's really madness to risk your body, risk your well-being and risk your happiness for money.

"Everybody, they just don't get it and they think it's crazy. But I think what I was doing is crazy."

Moffitt was placed on the reserve/left team list on Tuesday. To replace him, the Broncos activated J.D. Walton, who's had a long-term ankle injury dating back to last season.

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Aaron Wilson covers the Ravens for The Baltimore Sun.