Mike Tomlin takes over as the longest-tenured head coach in the ‘Big 4’ sports leagues with Gregg Popovich heading to the Spurs’ front office 😮‍💨 (h/t AndrewSiciliano / X) #miketomlin #steelers #pittsburghsteelers #steelersnation #steelersfootball #greggpopovich #nfl #nflfootball #pittsburgh