The decision by Werner comes just days after the 6-foot-3, 220-pound outside linebacker visited Ohio State for the Buckeyes' 30-27 victory over Michigan.
Werner is the second recruit in the Class of 2017 to decommit from the Fighting Irish in recent months. Four-star defensive lineman Donovan Jeter elected to back out of his commitment in October, shortly before committing to Jim Harbaugh and the Michigan Wolverines.
Werner is rated the 18th-best outside linebacker in the country in his class by Rivals, a national recruiting service.
Notre Dame's Class of 2017 now stands at 17 verbal commitments.