Per Alex Speier:
Bush joined the Red Sox in 2016 as an analyst working with minor leaguers before moving into a coordinator role following the 2018 season. He has worked with numerous Red Sox prospects on pitch design and pitch mixes, trying to maximize the effectiveness of their arsenals. In 2019, he also joined the big league team for multiple stretches, assisting former pitching coach Dana LeVangie.
Bush emerged as the clear front-runner from a pool of five candidates interviewed by the Red Sox this offseason prior to the hiring of Chaim Bloom as the team chief baseball officer.
Rather than reopening the search, in a sign of the much-discussed collaboration that Bloom and others in the Red Sox organization discussed at his introduction on Monday, the new Red Sox baseball operations leader was comfortable with the comprehensive process that led the team to promote Bush.