You know, I can respect his decision. We forget sometimes that the NFL is a job for these guys the same way our jobs are for us. He isn't hurting anyone by walking away. The worst is there is less depth on the O-line. And a guy playing without real passion for the game may be a bigger liability to the team than the guy that walks away just because he's not happy playing the game anymore.
It's his right to do what he chooses.
It would be different if this was the military and he quit on his brothers in arms during a firefight, or refused to deploy. Then I think we could pass some judgment on his character over it.
But the NFL is a job like any other. I would quit if I was unhappy in my job, why shouldn't a NFL player be able to do the same?
But what if this person you hired for said project was so unhappy doing it that he may be a liability to others on the job as far as safety and moral? Wouldn't you rather that person walked away than force that kind of risk on you?