ESPN.com initially reported the story.
Pavlik (40-2, 34 knockouts) is coming off his fourth straight victory with July's unanimous decision over New York's Will Rosinsky (16-2, 9 KOs), having burst onto the scene with a seventh-round knockout of then-undisputed and previously undefeated middleweight titleholder Jermain Taylor in September of 2007.
Pavlik, 30, was later dethroned as WBC and WBO 160-pound titleholder via unanimous decision by Sergio Martinez in April of 2010, and has since fought at or above 168 pounds.
"He's just not going to box anymore. He's decided to move on with his life. He's just not motivated to do this anymore. I think that he's happy with what he did, and that he's happy with what he has accomplished," said Dunkin.
"I don't think that there is anything else that he wants to do in boxing or he would stick around and do it. So he's not motivated to do it anymore, and he's put some money away. He's financially pretty stable. He's just not motivated to do it anymore."