It's the end of an era in San Antonio as head coach Gregg Popovich steps down from the role after 29 seasons leading the Spurs. While this is a seismic development in the NBA, it also has ramifications that bleed into the NFL as well.

Tomlin, the coach of the NFL 's Pittsburgh Steelers, started in his current role in 2007, so he took over for Popovich as the longevity in-one-place leader among the major pro leagues. Miami Heat coach Erik Spoelstra — who started in that job in 2008 — now becomes the coach with the longest current tenure with his team in the NBA.

The Pittsburgh Steelers' Mike Tomlin entered rare air on Friday. Now that the San Antonio Spurs' longtime leader Gregg Popovich has stepped down from his role at the helm, Tomlin is officially the longest-tenured head coach across the four major North American sports,