Say what you will, the employment conditions of these NFL football players are substantially different than the conditions of an ordinary person working at an ordinary job.
First, this is essentially a monopsony market where the NFL is the only employer. None of the secondary football leagues offer viable market alternatives to employment in the NFL.
Second, the National Football League Players Association (NFLPA) representing the "present and future employee players" and the National Football League Management Council (NFLMC) as the sole and exclusive bargaining representative of "present and future employer member Clubs of the National Football League" have entered into a little something called the Collective Bargaining Agreement. This agreement is littered with strictures. "All rookie players once they are selected in the current year’s NFL College Draft" become part of the bargaining unit that the National Football League Players Association represents. Turner, as a draftee in 2004, became part of the bargaining unit. He is both protected by and restricted by the terms of the CBA that was effectuated by the NFLPA and the NFLMC.
Third, in my opinion, one of the most pronounced restrictions can be found in Article 16 of the CBA:
"No player shall be permitted to apply for special eligibility for selection in the Draft, or otherwise be eligible for the Draft, until three NFL regular seasons have begun and ended following either his graduation from high school or graduation of the class with which he entered high school, whichever is earlier."
This notion is antithetical to a free-market system and the theoretical right to work. The CBA, therefore, affected Michael Turner before he was even permitted to become an "employee player" in the NFL.
Fourth, in return for a slew of terms that protect the interests of the league, the NFLPA has secured certain benefits for the members of the bargaining unit, of which Michael Turner is one. Michael doesn't have to practice as long. He gets paid more. He has certain rights when the team or the league tries to do things to him that are proscribed.
The notion, therefore, that teams owe players nothing because they are employees is very incorrect. In fact, the NFLPA has ensured through its representation of the players that a great deal is owed to the members of the bargaining unit, as anyone who has ever read the CBA can attest.
In return for these many benefits, the player employees are also limited in certain areas by the terms of the CBA, a fact identified by the original poster.
I am not arguing for or against unions or the agreement. I would suggest, however, that the upside of the CBA probably benefits Michael Turner more than the downside harms Michael Turner.