Lots of chatter that the Yanks are considering trading for a gold glove 3B and playing him at SS until Peraza or Volpe arrive. Aside from what seems like the more obvious move should they acquire Chapman - play him at his gold glove position, 3B, and let Urshela play SS. he is exactly the wrong type of player they should be adding, a right handed hitting low BA (.210 last year) high strike out type.
Both his BA and the underlying stats, exit velocity, hard hit rate, etc., have steadily declined the past several years. Even assuming Chapman would be an above average defensive SS, a position he has played all of 10 innintgs in the majors, they would probably be better off with the now departed Wade or Velasquez.
I've read about the chatter, as well.
Though, what you mentioned makes sense, and assuming the chatter is true, there would have to be a reason for it. When I read stuff about Chapman, the subject of Olson is sometimes attached to it. This could potentially be one of those deals that, in order to get Olsen, you agree to take Chapman.
Also, it's not set in stone, that if the Yankees were to acquire Chapman that they'll make him the SS. Cashman likes loves defensive flexibility. All in all, i do agree with you. If acquired, Chapman could ultimately be the 3rd baseman and Urshela the SS....we'll just have to wait and see.
Lastly, at this point, no one can say that either Wade or Velasquez would be better than Matt Chapman. Not even close. Chapman, on the steps of the dugout, getting ready to enter the batters box, would force the opposing manager to run virtual managerial simulations in his head. Someone lilke Wade or Vesquez, definitely would not.
Cashman and the front office, must have stats that leaves them to believe that he would be a suitable offensive player if he changed teams or perhaps some other factor(s). It's also possible, that Matt Chapman could be looked at, as another Scott Brosius. All in all we have to know and understand the CONTEXT of Chapman's numbers, before we can rightfully assess and make a prediction, whether he would be successful as a Yankee.