Kevin Kiermaier is so far and away the best fielder in the majors right now. He has easily the most defensive runs saved above average in the majors with 39 this means if every player were helping out the pitcher as much as Kiermaier the average ERA would be 1.36. Zack Greinke's already ridiculous 1.65 ERA would be 0.56. Kiermaier saved 139% as many runs as the second best player in that stat (Ender Inciarte, 28) and his dWAR (4.7) was 142% of the second best (Andrelton Simmons, 3.3).
In important situations Kiermaier's average throw speed from the outfeild was high in the 80s topping out at around 96 MPH. On top of that he made numerous diving plays making a clear choice for the gold glove and to me the Platinum glove as well. His solid offense is an addition that makes him one of the best players to be drafted in a round as late as the 31st round. This year his WAR is 7.1 making him 8th in the majors among position players. He was #3 on my underrated list this past year and is an almost certain choice to reappear on it next season.