From B******* R*****, http://bleacherreport.com/articles/1563123-elvis-dumervil-requests-release-from-broncos-following-contract-dispute
Since 2006, Dumervil has had some solid success with the Broncos, totaling 170 tackles, 63.5 sacks 16 forced fumbles and nine fumble recoveries.
He led the NFL in sacks in 2009 with 17, but then missed the entire 2010 season due to a pectoral injury. He had 9.5 sacks in 2011 and 11 sacks and six forced fumbles last season, but was being paid quite handsomely for his services.
Apparently, Denver doesn't quite feel his remaining salary is worth it.
Pro Football Focus reports that Dumervil had the third-lowest efficiency rating out of any Broncos player last season. Having said that, the defensive end still finished second on the team in sacks, quarterback hits and hurries.