Former Bears offensive coordinator Mike Martz resigned his post with the team on Jan. 3, and is now retiring from the coaching profession, according to a report by the NFL Network. A 20-year coaching veteran, Martz, who also served as head coach of the Rams, directed Chicago's offense to a pair of mediocre seasons in which it ranked 24th in total offense in 2011 and 30th in 2010, culminating in the coach leaving the Bears over what team president Ted Phillips called "philosophical differences."