The Bengals were tied for fifth in the NFL in fewest points allowed (19.1).
“I’m obviously very excited about this opportunity,” Guenther said in a release. “I like the players we have and what we’ve already done to get a good defensive team in place. I’m looking forward to working with all of them, in a new role for me, and continuing to improve us and make us better.
“I want to thank Mike Brown and Marvin for all they’ve done for me over the years and now for this chance,” he added. “And I also want to thank Zim for working with me so closely and helping me become a better coach.”
Guenther coached seven seasons at the college level, including four as head coach at his alma mater of Ursinus, where at the age of 25 he was the youngest college head coach in the country at the time he was hired.
He broke into the NFL ranks with the Washington Redskins in 2002, when Lewis was the defensive coordinator there.
He joined Lewis’ staff in Cincinnati in 2005.
“Paul and I have been mostly together since when we were both on the Redskins staff,” Lewis said. “I’ve seen him grow over the years and really have sort of been grooming him for this kind of opportunity.”