Use to be back in the day teams had a "never go back" unwritten rule meaning that once a FB player was traded or cut the team almost never wanted to give them another turn on the roster. Modern times are a bit different with salary caps and free agency rules now. But my gut feeling is the Cowboys and Zeke are done.
I think Zeke could get a chance somewhere in the NFL if, if, IF a few things fall in place. First: He must be willing to play for a lot less money than he is use to making. Second: He must convince some team the fire still burns and he wants to give his all. He needs to give the impression he still has something to prove. Third: The new team must really have a big need at RB and think Zeke can fill it. There are a lot of backs floating around looking for work. Competition for a roster spot could be tough.