Does a Promotion or Demotion Affect Relief Performance?

Over at The Hardball Times I looked at whether relievers who are demoted (or promoted) from Year 1 to Year 2 overperform their projections in Year 3.

Answering this question will help us understand what effect a demotion or promotion has on actual relief performance. Given today’s focus on relief pitcher roles, which despite Andrew Miller‘s 2016 postseason are still the norm in major league baseball, knowing this information could guide bullpen construction and roster management. Plus, the question is just plain interesting. So I dug deeper.