They’ve gone from the #1 team ERA in baseball last season to #17 in 2023 and, for the first time in years, seem to have a lack of trustworthy arms, especially in the starting rotation.
Why has LA Dodgers Pitcher Tony Gonsolin Become Unreliable?
Tony Gonsolin has surprisingly been one of those unreliable arms. After a dominating 16-1, 2.10 ERA, season in 2022, Gonsolin had big expectations to help lead LA’s rotation heading into 2023, even ranking top 20 in preseason Cy Young odds at +6000. If you want to learn a bit more about how baseball wagering works so you can bet on the Cy Young yourself, see the betting odds explained at Overtime Heroics.
So, what’s gone wrong for the young phenom from Vacaville? Well, it’s not exactly an easy question to answer.
Hard-hit Percentage
Looking at the overall numbers, one thing that immediately stands out is just how much harder batters are hitting the ball against him this season. His hard-hit percentage has jumped up from 35% to nearly 42%, dropping all the way down to the 33rd percentile league-wide. Even worse is his barrel rate, which just about doubled from 5.2% to 10.3%.
While batters are still hitting the ball at a relatively low rate against Gonsolin (.215 batting average against) they’re hitting it harder than ever before. The result is a woeful xSLG of .477, which is languishing all the way down in the 11th percentile among pitchers.
Okay, so we know that Gonsolin is having a tough time avoiding hard contact, but that’s more a symptom than the actual root cause. To really get into the why of his struggles, we need to dive into pitch tracking.
Pitch Tracking Deep Dive
Did you know that Gonsolin had one of the best pitches in MLB last season? His splitter was the best in the league by total run value, and the 4th most valuable high volume (min 500) pitch in all of baseball by run value per 100 pitches. And that wasn’t all. He also threw a filthy slider (2.4 RV/100) and an above-average curveball (1.8 RV/100), all of which more than made up for his admittedly pretty lackluster primary four-seamer. So, what happened?
Four-seam fastball
Let’s start with the good news. That mediocre four-seamer from last season has been far and away Gonsolin’s best pitch in 2023. His fastball batting average (.260 to .205) and slugging percentage (.473 to .364) have gone way down, although some of that can be attributed to good luck (.508 xSLG, 49.6 hard hit%).
Slider and Curveball
The real problem lies with the rest of his arsenal. That league-leading splitter from last season is still quite decent (.234 xBA, .364 xSLG) but nowhere near the same level. And that slider and curveball have completely fallen off a cliff, with a combined run value of -9 and an expected batting average north of .330.
At the end of June, Dodgers manager Dave Roberts singled out the slider particularly as a weak point for Gonsolin in 2023.
“I think the thing that stands out most is he just hasn’t had his slider. Versus left, the split-change, he manages hitters and he’s been fine,” said Roberts on SportsNet LA. “With right-handers, the equalizer has been his slider. And he just hasn’t had it. It just doesn’t have the bite, it’s been up the zone and he’s not getting the swing and miss that we’re accustomed to.”
Like Roberts said, the slider was Gonsolin’s best swing and miss pitch in 2022, with an impressive 36.8 whiff percentage. But its drop-off in 2023 has been nothing short of precipitous. That whiff percentage is now below 25%, and his expected batting average allowed on sliders has risen from below the Mendoza line to near .300.
The slider might not be the only factor at play, but it certainly seems to be the key to getting Gonsolin back into prime form. Getting a reliable third pitch back behind his four-seamer and splitter will help keep batters more off-balance and hopefully start putting a dent in those ugly hard-hit ball numbers.
Overall, Tony Gonsolin appears to have regressed across the board from his 2022 season, allowing batters to make hard contact at unsustainable rates and seeing the effectiveness of his slider and curveball plummet. For Dodgers fans, hopefully this is just a lingering symptom of early-season ankle issues, but it remains to be seen if he can once again capture lightning in a bottle.