The starting pitcher, at least as we once understood the term, is an endangered species. For decades, there were "starters," and there were "pitchers who weren't good enough to be starters." That's no longer the case, to put it lightly. In today's game, pitching staffs get built from the back end forward.
You know this because you're an educated baseball fan, and because you've seen enough games over the last few years to notice the nearly-endless stream of relievers entering from the bullpen. In 2017, we saw 610 different relievers appear in at least one game. That was a record, which broke the record that was set in 2016, which broke the record that was set in 2015, which broke the record that was set in 2014, and so on.
Conversely, 2017 pitchers tallied only 45 complete games, which was the lowest for a season in modern baseball (dating back to 1901). That broke 2016's record low, and 2015's previous record low, and on and on. You get the idea. This is the way baseball exists in 2018. There aren't really "starters" and "relievers," not like there used to be. We're on the inexorable march to seeing just pitchers.
It's not terribly hard to see why this is happening, either. In addition to some vague notions about lower pitch counts keeping pitchers healthier, the data clearly suggests that minimizing the frequency a tiring starter faces a lineup for a third or fourth time is smart strategy. This is what's known as the "third time through the order" penalty, which managers are less willing to risk than ever.
That's a bit of a misnomer, as pitchers don't magically turn into pumpkins when the leadoff man comes up for a third time, and it might actually be more about pitches than times through, but looking at it that way serves as a useful starting point. It's not hard to understand why managers would rather summon a fresh reliever than push a tiring starter, especially when you see how drastically the outcomes change.
Those numbers matter. A lot. Essentially, all batters facing a reliever for the first time in 2017 hit like Keon Broxton (.220/.299/.420), who found himself back in the Minors to start 2018. Batters facing a starter for the third time basically turned into Mookie Betts (.264/.344/.459), who already has a pair of top-10 MVP finishes under his belt.
The reasons why we see those outcomes aren't complicated, either. Relievers tend to throw harder because they don't need to worry about pacing themselves, and can instead go all-out for a handful of batters at a time (in 2017, relievers averaged 94.0 mph on their four-seamers, while starters threw 92.6 mph).
They can also drop their least effective pitches and focus on their strengths, which is often a bigger deal than you'd think, since starters usually need three or four or more pitches to fool hitters multiple times.
Consider Zach Britton and Andrew Miller, perhaps the best-known current examples of starters-turned-dominant-relievers. As starters, each threw four or five pitches. As relievers, they each dropped their least effective offerings - Britton no longer uses his four-seamer, changeup or slider, and Miller eliminated his sinker and changeup - to simply throw two good pitches all the time.
Relievers often get better platoon advantages, too.
Now, you might think that this is merely the late-stage culmination of a shift that began decades ago, and in some ways that's true. Looking back every 10 years as a snapshot going back to the 1970s, the number of relievers each team used per season increased by about two per decade, now nearly double what it was back in 1977.
But there's a different change that's only begun far more recently, one that's now having a separately massive impact on the game. As we just showed, the number of relievers had been increasing for years, yet the percentage of innings they were throwing hadn't. Relievers were throwing the same number of innings - it just took a lot more of them to do the job.
Think about it this way: In 1995, relievers (444 of them) threw 33.7 percent of all innings across the Majors. Twenty seasons later, relievers (538 of them) threw … 33.5 percent of innings. There were ups and downs in between, but nothing had really changed, other than more relievers splitting the same pie.
That began to change in 2015. Relievers threw 35 percent of innings, a record. In 2016, that went up to 36.7 percent. In 2017, it jumped to 38.1 percent. Based on the start of 2018, it seems possible that relievers will cross the 40 percent threshold for the first time.
In order to really see how much this change in philosophy has affected the game, consider two recent World Series games, played two years apart. Baseball has been around for well over a century, so two years wouldn't seem like a big deal. In reality, it felt like decades, based on how differently two managers handled their pitchers in the biggest spots.
On Nov. 1, 2015, in Game 5 of the World Series, with his team down 3 games to 1, Mets starter Matt Harvey threw 101 pitches through eight scoreless innings. With a 1-0 lead, New York manager Terry Collins intended to lift his starter in favor of closer Jeurys Familia. Instead, he allowed Harvey to talk his way back into the game. Harvey immediately allowed a walk and a double before he was removed. The Royals tied it up, eventually winning the game - and the Series - in the 12th inning.
"Obviously," Collins said after the game, "I let my heart get in the way of my gut. I won't be sleeping much the next couple of days. I'll tell you that."
On Nov. 1, 2017, in Game 7 of the World Series, Astros manager A.J. Hinch made a different kind of history. Starter Lance McCullers was tossing a shutout against the Dodgers through 2 1/3 innings, having thrown only 49 pitches. But McCullers was wild, hitting four batters, and all six of the balls in play he allowed were considered "hard-hit," i.e. struck with at least 95 mph or more of exit velocity.
Despite the zeroes on the scoreboard, it was clear McCullers wasn't exactly dominating. After allowing Corey Seager to single leading off the third, McCullers hit Justin Turner with a pitch, then struck out Cody Bellinger. Hinch called for the bullpen. Four Astros relievers combined for 6 2/3 innings of one-run ball. Houston won its first title.
It was the first time in World Series history - other than a pair of injuries and a 1920s gimmick - that a starter had been pulled before completing three innings while throwing a shutout. The kind of move that Hinch made would have been unthinkable two years earlier, just as Collins leaving in Harvey in 2015 seems unthinkable now.
"I didn't plan on pulling McCullers early tonight," Hinch said after the game. "I thought he was going to pitch a little bit deeper in the game, but what we were seeing were just some pitches that weren't being executed."
That's the entire point of all this, or really of any statistically-fueled revolution in baseball. Decisions have to be made on something more concrete than "well, this is the way we've always done it." The numbers have to help tell the story.
There are wide-ranging repercussions to all of this, of course. Starters who don't get to go five full innings can't get "wins," which means we'll see fewer 20-game winners (we didn't see any in 2017, one of only three non-strike seasons in history without one, all coming since 2006). That will necessarily change how awards are given out, and how contracts are structured.
On a larger scale, we may very well never see another 300-game winner, which will impact how Hall of Fame ballots are filled out. As of Opening Day 2018, there were only two active pitchers who had even 200 wins, and it's somewhat difficult to see either Carsten Sabathia (237 wins to begin 2018, and turning 38 in July) or Bartolo Colon (240 wins, and turning 45 in May) getting to the magical 300 mark.
It's a complete sea change in how you think about the role of the "pitcher," but then again, it's hardly the first time. For the first 50 years of the 20th century, starters routinely pitched 80 percent or more of all innings, with relievers entering only in case of injury or emergency.
In some ways, this is the truest form of baseball. Nowhere in the official rules of the game is "relief pitcher" defined as a position, other than to define things like when a save is awarded. There aren't starters and relievers. Just pitchers. So many pitchers.