The law regarding discrimination by private parties is found in Sections 2 and 5 of the Fourteenth Amendment.
[N]or shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws. . . The Congress shall have power to enforce, by appropriate legislation, the provisions of this article.
U.S. Const. Amend XIV.
The Fourteenth Amendment was passed after the Civil War to curtail slavery. Most Constitutional law is determined and written by the federal courts, but some things, like enforcing equal protection, and regulating Indian Tribes, are left up to Congress.
Congress has passed many landmark laws interpreting the Fourteenth Amendment including:
1. The Klu Klux Klan Act of 1871,
2. The Equal Pay Act of 1963,
2. The Civil Rights Act of 1964,
3. The Age Discrimination Act of 1967,
3. The Fair Housing Act of 1968,
4. The Americans with Disabilities Act of 1990,
5. There are lots of other 14th Amendment enforcement acts.
Of course, the federal courts interpret what these statutes mean, they just have to treat each 14th Amendment enforcement statute as if it is itself part of the Constitution, and cannot invalidate any part of it.
When evaluating the rights of an employee who is discriminated against by his company, we have to ask:
1. Is the discrimination against the employee based on his race, color, religion national origin or sex? (From Title VII of the Civil Rights Act).
2. Is it because he is old?
3. Is it because he is a woman?
4. Is it because he is disabled or pregnant?
If no to all, then its probably okay.
Although it gets kind of gooshy, the Equal Protections Clause only protects a person based on who he is, not on what he does. Private Americans routinely discriminate against the poor and those who show criminal tendencies.
Now, Doc's question is about Due Process. Should a person be shown some degree of due process in disputes at his workplace? The only federal law controlling how Employers treat all employees that I can think of is the Fair Labor Standards Act of 1938. The FLSA is made under Congress' power to regulate interstate commerce, and not under the Fourteenth Amendment Due Process Clause. The FSLA covers thing like minimum wage and the 40 hour work week and does not apply to millionaire football players.
The Fourteenth Amendment Due Process Clause generally only applies to state governments, and not to private parties. Is your kid being expelled from school without the principal hearing his side of the story? Due Process case. Did your boss fire you for your Facebook beer bong picture? Private problem, no federal case. Did your boss fire you because he heard of your Ramadan fast? Equal Protection case.
This is the law. Is it just?
I think that a companies' desire to dissasociate from a certain person is okay. A company has its own Constitutional rights, including Freedom of Association, and Freedom of Speech. If an employee does something that tarnishes the brand image of that company, the company has a right to dissasociate itself from that person, as long as it is following the Equal Protections enforcement statutes outlined above.
Here, The NFL is confronted with the footage of a player knocking his girlfriend unconscious and dragging her body from the elevator. This sort of footage is not endearing to female fans, its sponsors, or the general public, and has diverted attention from the on field product that the NFL is trying to promote. Did Ray Rice owe the NFL a hearing before he cost it millions in revenue and goodwill by his act? A company has a broad ability to dissasociate itself from unprofitable people in a free market.
To put it another way, what did the Baltimore Ravens ever do to deserve this?