Now that the 2017 MLB season is officially in the rearview mirror and the Winter Meetings are fast approaching, everyone around baseball has shifted their focus on 2018 -- even if the free agent market has been slow moving thus far.

A lot of the focus with regard to planning for next year is concentrated on front offices making roster moves, but players are also getting themselves ready, as they're likely deep into their respective offseason training programs. Whether they ended last year on a high note or a low note, there are plenty of hitters with plenty to prove once April rolls around.

The following five hitters are all at various points with regard to their careers, but they all have one thing in common. They should be taking the field next season with a chip on their shoulder.