Martinez is focused on improving his defense in 2017 after a down year in the field last season, MLB.com reports.
While defense doesn't immediately impact Martinez's fantasy value, it could affect his value in free agency next offseason. His defensive metrics all went down in 2016, but if he looks good in the field and at the plate in 2017, he could be in for a significant payday. Confidence also counts for something, so if Martinez is excelling in the field, it could carry over to his at-bats.