After just one season in Denver, defensive coordinator Mike Nolan has resigned from his position, reports the Denver Post. Nolan offered a brief comment, saying, "I can't say anything other than Josh and I mutually agreed to part ways."
Jay Glazer of FOX Sports was the first to break this news.
The move is especially surprising, considering that Nolan took the Denver defense from 29th in the league in 2008 to 7th this past season.
Miami, Buffalo and Chicago are all currently searching for a new defensive coordinator.
Nolan was the head coach of the 49ers from 2005-2008 after spending the previous 11 years as a defensive coordinator for the Giants, Redskins, Jets and Ravens.
Follow along for more on this story at SB Nation's Denver Broncos blog, Mile High Report.