Starters are just more valuable
Hitting is arguably the hardest thing to do in professional sports, but that doesn’t mean that pitching is easy. In fact, it’s precisely because the bar for successful pitching is so high that hitting is difficult—and it is why so many pitchers fail to meet that bar in the first place.
Drafted out of the University of Florida in 2018 as the 18th overall selection in the MLB Draft, Brady Singer sailed through baseball while making hitters look foolish. In his senior year of high school, Singer posted a 1.25 ERA and an 11.0 K/BB. In his sophomore and junior years as a starter in college, Singer posted a 2.90 ERA and a 4.4 K/BB. And in his career in the minors, Singer posted a 3.18 ERA and a 3.50 K/BB.
But in the big leagues, Singer is encountering true resistance for the first time. He owns a 4.86 ERA and only a 2.5 K/BB as a member of the Kansas City Royals. This year, his first full year, has been even worse—a 5.42 ERA and a 2.3 K/BB. With only so many rotation slots to go around, and with a relatively deep collection of intriguing upper minors arms, the Royals are going to have to make some decisions about who to send to the bullpen.
Should the Royals send Singer, however, to the bullpen? While he would undoubtedly be a very good reliever, he should probably remain as a starter even if he’s simply a bad starter.
We’ll get to why that’s the case in a minute, but let’s talk for a minute about why Singer would be a slam dunk reliever. The first is that his arsenal is suited for relief, primarily due to his lack of a changeup. This is a constant discussion point that is well-founded, as Singer only throws the pitch 3.4% of the time. Of the 81 starting pitchers with at least 100 innings pitched this year, 64 of whom—or 79%—throw the pitch more often than Singer, and 64% of whom throw a changeup twice as often as Singer.
Contrast with the numbers for relievers: of the 196 relievers this year with at least 30 innings pitched, 86 of whom—or only 44%—throw the pitch more often than Singer, and a whopping 39% of relievers have thrown precisely zero changeups. Singer has a great reliever’s repertoire, one that would only be served better by the velocity bump that starters get when they get moved to the bullpen.
Furthermore, we know that Singer would be a good reliever because he’s already really good when facing a lineup for the first time through the order. Of course, when you’re a reliever, you only face a few batters and don’t get past one time through the order.
For a pitcher like Singer who rarely gets to the third time through the order unless they’re doing really well or are left in the game for too long by the manager, those stats can look a little wonky, as they do here. But the biggest difference is between the first and second time through the order, where Singer sees a huge performance dropoff. That dropoff wouldn’t happen with him in the bullpen.
Finally, Singer moving to the bullpen would maximize his effectiveness against right-handed pitching. Teams know that Singer doesn’t have a changeup and can stack a lineup with left-handed hitters. But as a reliever, Singer could be deployed against a stretch of right-handers and dominate.
Singer actually strikes out righties at a lower rate, but two things are in his corner that more than compensate: one, that he walks them at a much lower rate; and two, that righties just can’t hit him for power.
So, yeah, Singer would probably be a great bullpen arm. He wouldn’t need pinpoint control to unfurl 96 MPH running fastballs and wipeout sliders for a couple of batters. There are many worse starters than him who have had success as a relief pitcher—Luke Hochevar and Wade Davis immediately spring to mind.
But therein lies the problem: pretty much every good starter would be a really good reliever. Of course Max Scherzer would be a killer bullpen arm. However, he is not a killer bullpen arm for a simple reason, that reason being that he’s already a killer starting pitcher.
Additionally, you don’t have to be a good starting pitcher to be a more valuable starting pitcher than you would be as a relief pitcher. That’s because starting pitchers are simply much, much more valuable, and you would be surprised at how much more valuable starting pitchers are.
To illustrate just how wide this talent disparity was, I pulled single-season pitching data since 2010, excluding 2020 for its pandemic-shortened nature. I wanted to look at healthy performances, so I included every individual season for each player who pitched at least the median innings from the dataset (82 or more innings for starters, and 23 or more innings as relievers) over two or more games. Then, I sorted it into quintiles by Fangraphs’ version of Wins Above Replacement for easy comparison between similar buckets.
The result? Even the worst starting pitchers are more valuable than the majority of bullpen arms.
The data could not be any clearer. If you’re healthy enough to turn in at least the median amount of innings as a starter, you are almost guaranteed to be more productive than your reliever counterparts. The bottom 20% of healthy starters turn in as much production as the bottom 60% of relievers. And the wildest thing is that a lower-3rd quintile or upper-4th quintile starter provides as much value as the very top quintile among relievers.
There are some qualifications to be made here. If you’re bad enough, you won’t hit the median innings pitched requirement to be on the list—in other words, you can absolutely be a worse starter than most relievers. But the same is true in reverse, and it’s why I wanted to look at healthy seasons with players who had a bare minimum talent level to pitch a median amount of innings.
In Singer’s case, even a 4th quintile production level would be much more valuable to the team than all but the best relievers. That is why he will be given every chance to succeed as a starter, and it’s why he should be given every chance to succeed as a starter.
Still, there’s a future where Singer gets shifted to the closer’s role. But that future depends entirely on his teammates forcing him out of the rotation rather than the Royals specifically putting Singer in the bullpen. Considering the struggles of Brad Keller, Kris Bubic, and Mike Minor this year, that is unlikely to happen anytime soon.