Mackowiak can play 2nd base. He has started 15 games there so far this season. If you don't think he's good enough defensively there, we would also have Ozuna to backup 2nd base.
And the Pirates would trade Mackowiak anyways, in my opinion. He is only under a 1-year deal right now and they will just owe him more money for next season. Dumping salary for cheap talent is the Pirates' way.