Below is a graph. It is a simple graph. It does not use advanced statistics, although any number of advanced statistics could show a similar trend. It is a graph of Andrew Miller’s innings pitched (red) and ERA (blue).
For our purposes, of course, only the years 2016 to present are of interest. In 2016, the Indians acquired a legitimate ace of a reliever, evident by the huge gap between innings and ERA above. That reliever commanded a king’s ransom, but he was kind of guy that turns a good ballclub into a World Series team.