In terms of contracts they are in the same situation, the difference is the worth of said contracts and how much a club could demand from the manager if he unilaterally broke it. The difference for players is the FIFA registration a player cannot play without being registered and FIFA generally don't allow the transfer of registration when players are involved in legal conflicts.
Yeah this makes sense. So it's easier to free a manager than a player. Thanks for the explanation!
We had a discussion about this in the context of the strange managerial carousel of last season's Bundesliga.
Legal issues aside, the thing worth keeping in mind that at the end of the day it's just impractical for a club to force a manager to continue in his contract when he clearly wants out, as the position of the manager and its performance is so sensitive and influential for the performance of the whole team. It's just too big of a risk.
It's possible, even if not particularly helpful, to force a player to stay, and if he sulks and doesn't perform, one player can be benched without the whole team tanking. If a manager is refusing to perform or his performance negatively affected by the situation, it affects everything, and the facts will sooner or later necessitate a sacking anyway. See as an example, Favre in his last, very short, season at Gladbach.
That's another reason why the transfer market for managers isn't like it is for players.