Thanks to the magic of Statcast and PITCHf/x before it, the means by which to evaluate pitchers have grown exponentially. Beyond ERAs and per-nine rate stats — and beyond DIPS, FIP, and BABIP, too — we now quantify pitch usage, velocity, spin rate, movement, whiff rates, pitch tunnels, quality of contact and more. It can get dizzying, and you can find some way in which just about every pitcher this side of Clayton Kershaw is below average. Last year, 68 pitchers threw at least 120 innings and finished with an ERA- below 100. Only 54 finished with a FIP- below 100, as well. Raise the bar to 162 innings and the count falls to 32 pitchers, occupying 21% of the majors’ 150 rotation jobs. As balls fly out of the park at record paces, relatively few starters have enough stuff to dominate. The vast majority are just trying to command a fastball well enough to get a shot at fooling hitters with their offspeed stuff.
Given 30 major-league rotations, 15 have to be below average, and among them are all too many pitchers easy to ding for their middling velocity, lack of command, failure to get hitters to chase their breaking stuff, or inability to stay healthy. Their projections inevitably look dire or at least uninspiring, and writing about them can feel like shooting fish in a barrel. Yet even among these lesser rotations, tiny miracles that defy our projections occur all the time. A pitcher learns a new grip, or irons out his mechanics, or gets a competent defense behind him. Suddenly, he’s living up to the visions of the men who scouted him, or at least outpitching the numbers that tell us all of the ways in which he is lacking.
Based upon the projections, less than two wins separates the 16th-best rotation here (the Angels) from the 25th best (the Tigers). Much of the difference rides on our best estimates for the number of innings the top-eight or -nine guys in these organizations will throw — estimates that can be wiped out with the bad news about a single ligament, tendon, muscle or bone. Some of these rotations will be ghastly, but some will pull it together, defy our projections and perhaps even carrying their teams to playoffs thanks to a few tiny miracles. Projections, after all, are not destiny.
Brooklyn-based Jay Jaffe is a senior writer for FanGraphs, the author of The Cooperstown Casebook (Thomas Dunne Books, 2017) and the creator of the JAWS (Jaffe WAR Score) metric for Hall of Fame analysis. He founded the Futility Infielder website (2001), was a columnist for Baseball Prospectus (2005-2012) and a contributing writer for Sports Illustrated (2012-2018). He has been a recurring guest on MLB Network and a member of the BBWAA since 2011. Follow him on Twitter @jay_jaffe.