Coach leaving New Girl only to be swiftly replaced with the character of Winston is still a move that puzzles many viewers. Winston and Coach's New Girl swap was the first big mystery in the show, which premiered on Fox in 2011 and came to an end in 2018 after seven seasons. The series, created by Elizabeth Meriwether, followed Jess (Zooey Deschanel), a bubbly teacher who, after a bad breakup, moved into an apartment with three less-than-mature men to begin a new life. Jess’ new roommates were Nick (Jake Johnson), Schmidt (Max Greenfield), and Coach (Damon Wayans Jr.). Winston (Lamorne Morris) joined the group in the second episode of New Girl.
https://screenrant.com/new-girl-pilot-coach-winston-replaced-reason/