Defensive stats do need a significant sample size so do many of the batting and pitching numbers that are heavily used on almost any baseball telecast. Not only are these stats presented as meaningful in a partial season sample they are often used in splits that further degrade the sample. One 2018 article with some discussion of the reliability of defensive metrics and reliability. https://blogs.fangraphs.com/statcasts-outs-above-average-and-uzr/ Defensive stats have evolved since 2012 but here is an early article on their reliability. They have improved since. https://www.billjamesonline.com/how_well_do_advanced_defensive_statistics_correlate/ I join those of you that are skeptical of defensive metrics in samples smaller than a full season or even more. I think we should be just as skeptical of slash stats, ERA, FIP and others that are much more commonly cited.