Marinelli opts to leave Bears

Rod Marinelli will not return as the Chicago Bears' defensive coordinator next season.

New coach Marc Trestman said Marinelli has ''made up his mind to move on.'' It was not clear Thursday who will replace him.

''I would have hoped Rod would have stayed here,'' Trestman said. ''We had a great conversation. We've got mutual friends that we worked with, that know each and every one of us. I don't think that was an issue, but the NFL moves quickly. We've got to do our due diligence. ... We want to get the best guy in here.''

Marinelli is a longtime friend of former coach Lovie Smith, who was fired by the Bears after they missed the playoffs for the fifth time in six seasons.

Marinelli was hired as the Bears' defensive line coach in 2009 and spent the past three seasons as coordinator. Before coming to Chicago, Marinelli went 10-38 in three years as the Detroit Lions' coach and was fired after failing to win a game in his final season.

''I think at the end, he was looking for a transition,'' general manager Phil Emery said. ''He was looking to move in a different direction. He felt he needed a fresh start and that we needed a fresh start.''

He said he thinks the Bears will have most of their staff set by the middle of next week. Trestman said he might bring in some of his assistants from Montreal.