Since 2009, Rick Porcello and Justin Verlander were constants in the Detroit Tigers' rotation on a steadily changing team where players come for a few years and exit, prospects never get too comfortable, and Dave Dombrowski trades everything not nailed down. We grew accustomed to Rick and Verlander in the rotation, and this is one reason why many people were not excited when the Tigers traded Porcello during the offseason (in addition to the obvious concern that thinning the rotation puts more stress on the bullpen and lo, is the rotation thin).
Porcello and Verlander were separate characters traversing a similar arc — Verlander was the mentor and Rick the youngster who couldn’t quite put it all together.