A backup shortstop can be an underrated part of a Major League team. Right now, there is no clear cut backup shortstop for the 2017 Pittsburgh Pirates. But there are multiple options.
The Bucs could look to fill internally with players such as Gift Ngoepe or Chris Bostick. They could also look to the free agent and trade markets. Although, I believe the ladder options are pretty unlikely.
Another factor here is if the Pirates believe Jung Ho Kang can still play shortstop or not. He has not played shortstop since his catastrophic leg injury in September of 2015. And many people, myself included, came to the assumption after that injury that he would never play shortstop again.
If Jung Ho Kang can play shortstop in 2017 then the case is settled. On days Jordy Mercer is not in the lineup Kang slides to shortstop and David Freese starts at third base. However, it is unlikely that Kang will be able to play shortstop in 2017.