In order to take the next step, he may need to tweak his arsenal.

If you’ve ever spent too much time playing a game like League of Legends, you’ve probably heard the term “meta”. If you’re like me, you quit quickly after realizing how difficult it was and may need additional explanation. The meta in a game is basically a collection of the most viable, advantageous strategies based on the game’s rules. If the game is updated, the meta changes and new strategies become practical.

Much like a video game, baseball has a meta. It might not be discussed in the same way, but it exists, and it’s changing faster than ever. Pitchers take a new approach, hitters eventually adjust, and the cycle continues. Part of the current meta is the high fastball. While the high fastball has always been en vogue, it’s more popular now than ever, and hitters are starting to catch up.

Eno Sarris gave some history on the latest trends in pitching and broke down the newest strategies for pitching at the top of the zone before last year’s World Series. If you have a subscription to The Athletic, I highly recommend reading his piece before going any further. If you don’t have access, the gist of Eno’s work is that while a hitter can’t detect the rising effect a four-seam fastball has, they’re adjusting by swinging higher than they otherwise would when they identify a pitch as a four-seamer. Pitchers, in turn, have adjusted by throwing more sinkers at the top of the zone. They look like high fastballs but don’t have the same rise, and hitters are swinging over them as a result. My two sentences don’t do Eno’s work any justice, so again, I’d recommend reading his breakdown if you have the opportunity.

After reading the piece and subsequently watching Corey Seager take a Paul Sewald rising fastball 400 feet in the World Series, I’ve been interested in the relationship between high fastballs and high sinkers. While the new wave might be to use the sinker high, conventional wisdom is to keep the ball down. The low sinker will probably always be in style, but the new thinking may have some merit.

Note: for the purposes of this article, sinker and two-seamer are used interchangeably. While some might argue they’re different, I disagree, and the thesaurus doesn’t include baseball terms.

So, what makes a high sinker work? At the end of Sarris’ article, he mentions how one coach said throwing both a four-seamer and a two-seamer is a “cheat code” because the two fastballs often look so similar, and have similar velocities. That’s where I went looking first. I took a data set of all the high sinkers thrown in 2023 by pitchers who threw at least 50 total sinkers and labeled each of them based on the pitchers’ “primary fastball” (i.e. sinker or four-seamer). Pitchers who use a four-seamer more often than their sinker saw higher swing rates (swings/total pitches) and swinging strike rates (whiffs/total pitches) than those who used primarily a two-seamer. Those pitchers also see lower “Ideal Contact Rates” on those pitches, which is a great way to measure results when a pitch is put in play (More on that here).

The results aren’t crazy by any margin, but there is a fairly clear distinction given the sizeable sample. At a glance, this all makes a lot of sense. If a hitter sees a high fastball and swings expecting a “rising” four-seamer, but instead gets a sinker that ducks below the bat, they’re less likely to make contact or more likely to hit the ball poorly if they do connect.

To further explore the relationship between the four-seamer and the high sinker, I attempted to measure a pitcher’s intent with their fastballs. To do so, I bucketed four seamers into locations based on their height relative to the batter and calculated the percentage of pitches that were high for each pitcher. PitcherList.com shows “hiLoc %” on their player pages, my calculation was as close as I could get without knowing their definition of “high”. The head of the site, pitching guru Nick Pollack, has previously used 60% hiLoc as his mark of “intent”, so I did the same.

Among pitchers who are using their four-seamer up in the zone more often, we again see improvements in swinging strike rates, whiff rates, and ideal contact rates against the high sinker. This could be a result of pitchers in the first group having better overall command, but it also supports the conclusion that the elevated two-seamer is a great compliment to the four-seamer.

Now that we’ve established that using a four-seamer helps keep hitters off the high sinker, we can go even further in detail by looking at platoon splits.

Again, we see similar results in both splits. More swing, more whiff, worse contact. What’s particularly interesting though is the results against opposite-handed hitters. Today’s book says to throw two-seamers inside to same-handed hitters and avoid them against the reverse. Here, we can see that if a pitcher has a four-seamer, the elevated sinker plays much better against opposite-handed hitters. For a pitcher who relies on a slider or sweeper, the high sinker could be a good compliment to the high four-seamer. The only caveat is the ICR rates are higher, but that’s to be expected with all sinkers to the opposite hand. So, if you’re a right-hander with both fastballs pitching to a lefty and you’re looking for a whiff, the high sinker might not be a terrible idea.

I’ll also point out the decrease in ICR rates against same-handed hitters where the pitcher has a four-seamer. If you’re looking for a high fastball and that pitch runs in on your hands at the last minute, the possibility of a jam shot increases. Funny enough, Marquee Sports Analyst Lance Brozdowski put out a video discussing the interaction between four-seamers and two-seamers against same-handed hitters on Wednesday. Feel free to give that a watch after you finish here.

You may have noticed Brayan Bello’s picture at the top of this article and are wondering what he has to do with any of this. We’re getting there, I promise. In Bello’s first full season with the Red Sox, he had ups and downs. Against right-handed heavy lineups (see: Yankees), he was as good as they come. Against those with more lefties, he struggled. Here’s a look at Bello’s platoon splits in 2023:

And here’s how he’s approaching those hitters:

There are two very distinct approaches here, and it’s clear the approach against lefties isn’t working. For Bello to go from good to great, he needs to find a way to succeed against both sides of the plate.

As a pitcher in any count, there are two goals, either earn a strike or record an out. When you’re ahead in the count, you’re at an advantage over the hitter, and recording an out should be easier. In 2023, when Bello was ahead in counts against left-handed hitters, he threw over 40% four seamers. On those pitches, lefties slugged .615, with an ICR rate over 40%. Simply put, that’s not good enough. Overall, the pitch shape doesn’t suggest it would be great at the top of the zone, but Bello needs something besides his changeup to use against lefties, and sinkers and sliders don’t typically play well against the opposite hand, leaving him with just that fastball. He could try to develop a cutter or experiment with his four-seamer to be more successful. Those are probably good ideas in the long term, but they might not happen overnight. A quick fix, at least for now, might be the elevated sinker.

Bello is clearly committed to the high fastball approach; 63% of his four-seamers to lefties were “high”. Unfortunately, that didn’t bother hitters, as shown by those horrific numbers above. If hitters are going to continue to try to punish those high fastballs, mixing in more two-seamers could solve some issues. The two fastballs have similar spin out of his hand, but very different movement profiles. As we saw, if hitters are reading high four-seamer, and instead get high sinker, they may swing right over it and either whiff or make poor contact. While I don’t have the analysis to back it up, I also wonder if a willingness to throw the high sinker can keep hitters off the four-seamer; it’s all one big game of cat and mouse after all. Perhaps that’s a research topic for midseason as more pitchers adopt the approach.

Any edge matters in pitching, and Brayan Bello needs to find an edge to truly become the ace some believe he can be. The elevated sinker may not be the answer for Bello, but the numbers suggest it’s worth a shot.