The righthander from Athens, GA was a Rule 5 draftee of the Astros before the 2013 season. He compiled a 9-10 record a 4.53 ERA and nine saves over 3-1/2 seasons before he was traded at the 2016 deadline to the Dodgers for Cuban slugging prospect Yordan Alvarez.

His game improved with Los Angeles through 2018 and has posted career totals of 17-12 with a 3.71 ERA and 13 saves. Fields appeared in the 2017 World Series against the Astros and allowed two runs without registering an out.