After President Donald Trump said that any NFL member who does not stand for the national anthem should be fired, the Steelers decided to make a counter-statement by staying in the locker room during the national anthem.  The players didn’t have any issue with the anthem itself, but were making a statement that the president should not be telling them what to do on or off the field.

Alejandro Villanueva was the single member of the team who broke ranks and came out onto the field to stand for the national anthem.  After graduating from West Point, Villanueva served as a Platoon Leader in 10th Mountain Division and then attended the Ranger Orientation Program (ROP) and made the cut, going on to become a Platoon Leader in 1st Ranger Battalion.

https://www.youtube.com/watch?v=4HR6fhif9CU