Not that we didn't already know this, but just to put it all into context...
Here's a quick-reference glossary so we're all on the same page.
Innings: Number of innings played in center field.
RZR: Proportion of balls hit into a player's zone that have been converted into an out. Read like fielding percentage, only a much more accurate assessment of ability.
OOZ: "Out of Zone", or the number of outs converted outside of a player's zone.
UZR/150: Runs above (in Gomez's case) average per a full season (considered 150 games).
RngR: Range runs above average.
RF/9: Range factor, one of the older defensive metrics, given a value per nine innings.
Given the fact that Gomez is still sixth in making plays outside the zone of an average center fielder, in spite of being near the bottom of the list in terms of qualifying CF's due to his number of innings, says a lot about Gomez's range. In fact, and it's no surprise, it's his greatest asset and we're seeing that translated into one of baseball's best defensive performances in center.
Oddly enough, Gomez came in first in a lot of these categories last season; he made 104 outs out-of-zone as well. Enjoy this display of athletecism while you can, because at 23 Gomez isn't going to get any faster.