This Major Brayan Bello Change Might Unlock Red Sox Starter’s Potential

Brayan Bello threw 2,518 pitches during the 2023 season, and nearly 21% were four-seam fastballs. Eighty-four pitches into a new season, it appears the Red Sox pitcher's four-seam percentage is about to fall off a cliff.

Bello was effective Thursday night, allowing just two runs over six innings in Boston's Opening Day win over the Seattle Mariners. While he only struck out two Mariners, he did get eight swings and misses while also inducing seven ground balls, including a first-inning double play to hold Seattle at bay. A lot of the Mariners' contact was weak, as they failed to connect strongly with the ball.

A big reason for that weak contact was Bello's pitch usage. Of his 84 pitches, 36 of them were his sinker (or two-seam fastball), and he also relied heavily on a changeup (28 pitches) while mixing in his slider (20 pitches). Add that all up, and you get 84, meaning Bello didn't throw a single four-seam fastball Thursday night, at least not according to MLB's own pitch-tracking data.

(He also ditched a seldom-used cutter, too.)

Again, the four-seam numbers are a massive departure from his big-league career to this point. Bello threw four-seamers 19% of the time in his rookie season and he increased it to 20.6% last season.

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Obviously, it's worth wondering whether this change is here to stay and whether this is part of the Red Sox's new pitching infrastructure led by chief baseball officer Craig Breslow and pitching coach Andrew Bailey.

In fact, the change -- albeit in the smallest sample size imaginable -- does seem to have Bailey's fingerprints (perhaps literally) all over it. It's not dissimilar to what Bailey did with Giants pitcher with Giants pitcher Logan Webb when Bailey held the same position in San Francisco.

Webb threw his fastball nearly half the time when he made his big league debut in 2019. A year later, his first with Bailey, he threw it a third of the time, a rate that dipped below 10% in 2021 and was 3% in 2022 -- when he went 15-9 with a 2.90 ERA.

Last season, leaning on the sinker-changeup-slider combination, Webb finished second in National League Cy Young Award voting after signing a five-year, $90 million contract extension in April.

Game 1 starter Logan Webb credited Brian Bannister and Andrew Bailey for helping him figure it all out this year and come up with a new pitch mix. Said "it took a lot of sucking" to get it right.

— Alex Pavlovic (@PavlovicNBCS) October 7, 2021

If Bello is following a similar path, it certainly makes sense. Last season, opposing batters slugged .646 against his four-seam fastball. It was by far his worst pitch with the rarely used cutter a close second. His best pitch was his changeup that opposing hitters slugged .291 against with a 39% whiff rate.

"There's addition by subtraction, as well," Bailey explained to reporters at Red Sox Winter Weekend in January. "One of your pitches may play better than another.

" … If you look over a long period of time at the best pitchers at the major league level, you know what they're going to do to both right-handed and left-handed hitters. They have a general attack plan and they don't get off that. Cleaning up the gray area there and doubling up on strengths is going to be huge."

So far, so good in that regard. It's far too early to tell whether Bello is about to take a massive step in his progression or whether the rest of the Red Sox pitching staff will benefit from Bailey's blessings. But the early returns sure are encouraging.