One of the biggest knocks against Mike Tomlin is his lack of a coaching tree. Not many coaches who have worked under Tomlin have gone on to make a significant impact as a coach elsewhere, with the exception of a few veteran coaches like Todd Haley or Bruce Arians. But those coaches wouldn’t be considered a part of Tomlin’s coaching tree. It’s a tree that’s barren, but this offseason, it could see new life. With Detroit Lions OC Ben Johnson expected to leave Detroit for a head coaching gig, ESPN’s Adam Schefter reports that former Steelers wide receivers coach Scottie Montgomery, now with the Lions as their assistant head coach/running backs coach, could receive OC consideration in Detroit.