Mike Tomlin told CBS that his players would remain in the locker room and not be on the field during the national anthem, in the aftermath of Donald Trump’s comments.
However, there is a league rule, which requires the players to be on the sideline during the national anthem (but does not regulate that they stand, sit, kneel, etc.)
"Responding to a tip from one of his “boys,” Smith brought up the fact that until 2009—eight years and a new Presidential administration after 9/11—players weren’t on the field for the national anthem and instead generally remained in the locker room. According to Smith’s boy (and the researcher at ESPN who checked it), the switch happened “because it was seen as a marketing strategy to make the athletes look more patriotic.”"
We’ll see if the Pittsburgh Steelers follow through with Mike Tomlin’s statement, and whether the NFL has any response for staying off the field entirely.