We are about 2/3 through the 2023 season. The days are getting shorter, which of course means winter is coming. Most unexpected hot starts have been picked up and the stragglers dropped. Now we’re switching gears to buy low/buy high guys in trades. To make the best possible trade decisions we need to know what’s real and what isn’t. Sample sizes are even large enough to not just look at 2023 stats as a whole.
Kodai Senga, SP, New York Mets
The Mets got Kodai Senga from Japan before the 2023 MLB season. He is a 30-year-old RHP that came with a reputation of a SP with great stuff, but questionable command. So far in 2023, he has posted a 3.17 ERA, 1.24 WHIP, 29.1% K%, and 11.9% BB% in 105.0 IP. It looks like those scouting reports were spot on.
In 23.1 IP in July he has a 31.9% K%, 7.7% BB%, 1.93 ERA, and 0.86 WHIP. A 24.2% K-BB% would be fourth best in 2023 amongst all qualified SP. Throughout the year his K% has been increasing modestly while his BB% has been dropping steadily. He must be throwing more pitches in the strike zone right?
Nope. His Zone% has actually dropped from 43% to 38%. This is 63rd out of 66 qualified SPs. He’s increased his Swinging Strike% from 11.2% to 12.9%. He seems to have changed his pitch usage somewhat to entice more swings out of the zone. He started off by throwing his four-seamer at about 45% and dropped its usage to around 30%. His cutter and splitter/forkball have picked up that 15%.
Verdict: Not legit. Recently Senga has been pitching like an ace. This appears to be largely due to taking advantage of aggressive hitters. Once word gets around about his pitch usage change I suspect hitters will begin to swing less. Once this happens his BB% will increase and he will return to being a good, but wild mid-tier SP that limits hard contact, has a strong K%, and a poor BB% which lowers his WHIP ceiling.
Brayan Bello, SP, Boston Red Sox
Brayan Bello is a 24-year-old rookie who was the Red Sox’s 3rd-rated prospect and 38th overall according to FanGraphs. In 2022 he had a 4.71 ERA, 1.78 WHIP, 20.5% K%, and 10.1% BB% in 57.1 IP. Similar to Senga he had a reputation in the minors as someone with good stuff, but FanGraphs gave him only a 30/40 Command grade. Those guys almost always end up being relievers. Going into his July 31 start he’s posted a 3.66 ERA, 1.21 WHIP, 20.3% K%, and 6.4% BB% in 96.0 IP. Not really the K% and BB% you’d expect given the scouting report. His 56.2% GB% has likely been the most significant contributor to his success. If he Qualified, that would be the 4th best in all of baseball, behind just Logan Webb, Marcus Stroman, and Alex Cobb. Bello has posted high groundball rates throughout his minor league career.
Bello primarily throws a sinker (35%), changeup (24%), four-seamer (22%), and slider (18%). The sinker and slider are responsible for the high GB%. Overall, the sinker is likely his best pitch. It generates above average O-Swing%, Swinging Strike%, and GB%. PLV also likes it (78th percentile), but Stuff+ does not (93 Stuff+). The rest of his pitches are mediocre at best.
Verdict: Not legit. It’s hard to trust someone who relies almost entirely on groundballs, hard-hit groundballs. Bello’s Hard Contact% is 30.8%, that’s 18th percentile. I will say that in the minors Bello’s K%’s were typically closer to 30%. Coupling those types of strikeout numbers with strong GB% (even if that means higher BB%) is a much better combination. I’ll be more convinced if he starts to generate more swings and misses.
Jarren Duran, OF, Boston Red Sox
Jarren Duran is 26 years old and was a 7th-round pick by the Red Sox in 2018. In his last full season in MiLB in 2021 he was FanGraphs’ 52nd-ranked overall prospect. He had a reputation as a speedster with a good hit tool, but below-average power. In brief stints with the Red Sox in 2021 and 2022, he really struggled. There’s nothing good about any of those numbers below. A player can certainly be expected to struggle during his first taste of MLB, but at 24 and 25 years old Duran wasn’t super young.
He looks much better in 2023. He’s probably had a bit of batted-ball luck as his AVG is .315 and his Statcast xBA is .271 and Pitcher List’s xAVG is .256 (BABIP of .413 if you prefer that metric), but that is usually expected with that high an AVG.
Verdict: Legit. With Duran’s speed (96th percentile) he would have a decent AVG and a lot of SB simply by slapping the ball. In 2023 he is doing more than that. A .196 ISO is not great, but good. 82nd percentile Max EV and 80th percentile Hard Contact% is more power than what he showed in the minors. He only has 6 HR, but is 4th in MLB with 31 doubles. With the doubles power he has shown and a steadily reducing K%, he should continue to be a good source of AVG, SB, and R.
Cody Bellinger, OF, Chicago Cubs
Just about everybody knows the Cody Bellinger story. A budding superstar with the Dodgers from 2017-2020 before a freak shoulder injury in the 2020 playoffs seemed to turn him into a much-reduced version of himself. He joined the Cubs in 2023 trying to revitalize himself in his age 27 season. So far, it seems to have worked.
His K% has returned to 15.9%, which is comparable to what it was in his 2019-2020 seasons. This is the primary reason his wRC+ has returned to an excellent 140.
Verdict: Legit. It seems very simple. He’s traded some exit velocity for much more contact. A slightly more open stance may have contributed to this. It’s odd that a decrease in Hard% and an increase in Soft% coincides with an increase in wOBA, but he recognized that he just needed to make more contact. He’ll likely never return to that 47 HR number from 2019, but I’m convinced he is back to being a very good player.
Featured image by Doug Carlin (@bdougals on Twitter)