That's not what the title of the thread conveys. The title of the thread suggests that NFL players don't have Free Speech rights. That's why I said you titled the thread poorly.
That's because they don't have free speech rights. A "right" is something that people can do or not do without negative consequences. One cannot say someone has a "right" to free speech but at the same time claim they can be fired for exercising that right. If they can be fired, the right does not exist.