Jon Gruden to return as Oakland Raiders coach. But how did he get the nickname Chucky?

OAKLAND, Calif. - Jon Gruden is expected to be formally knighted as the newest Oakland Raiders coach on Tuesday morning, returning to a team he previously coached two decades ago.

He replaces Jack Del Rio, who was fired on Dec. 31.

Gruden knows about being let go from the Raiders. The late owner Al Davis traded him to the Tampa Bay Buccaneers in 2001, where he beat the Raiders in the 2003 Super Bowl as Tampa's coach. He's been a "Monday Night Football" commentator since losing his job with the Buccaneers in 2008.

When he was with the Raiders starting in 1998, Gruden earned the nickname "Chucky." Some say it was Raiders defensive team lineman Grady Jackson, who thought his coach looked like the fictional character in the slasher movie Child's Play, who gave him the name. Sports Illustrated, however, credits running back Harvey Williams who gave his coach the name after receiving a torrent on criticism, noting Gruden's arching eyebrow and lopsided grin. 

The resemblance between the character and Gruden are uncanny, some say, especially when Gruden is scowling on the field.