Brandon Williamson's first start since Tommy John surgery was a disaster.
On March 31 at Great American Ball Park, he faced the Pittsburgh Pirates and lasted only 4.2 innings. He gave up six hits, six earned runs, three home runs, and two walk. He seem overmatched the whole game as opposing batters hit him hard while he managed to only three strikeouts. His ERA after one start: 11.57.
For a 28-year-old lefty making his way back from major surgery, it was the kind of outing that makes a fan base hold its breath for the wrong reasons.
Six days later, Williamson took the mound against the Miami Marlins and threw 6.2 innings of three-hit, shutout baseball. One walk. Four strikeouts. A well-earned win that reminded fans the high ceiling he flashed before his injury.
He didn't simply perform better — his underlying pitch data says he basically became a different pitcher between starts. During those six days, he worked closely with the Reds pitching coach, Derek Johnson, to overhauled his pitch mix, leaning into his changeup and cutter while shelving his sinker and slider. The results, as we saw, were nothing less than stellar.
What He Threw
When you look at Williamson's pitch mix vs Pittsburgh and vs Miami, he looks like two completely different pitchers.
| Pitch | 2023 | vs Pittsburgh | vs Miami | Change |
|---|---|---|---|---|
| Changeup | 16.5% | 12.8% | 28.0% | +15.2 |
| Cutter | 29.8% | 20.2% | 28.0% | +7.8 |
| Fastball | 37.2% | 24.5% | 21.5% | −3.0 |
| Curveball | 6.4% | 9.6% | 10.8% | +1.2 |
| Slider | 10.2% | 19.1% | 6.5% | −12.6 |
| Sinker | — | 13.8% | 5.4% | −8.4 |
His fastball velocity was nearly identical in both outings, 93.1 mph (which is actually higher than his 2023 average velo). So it's not like he's got less arm, he just needed fix in his approach.
Back in 2023, he was a fastball, cutter, and change pitcher, but he swapped out the latter two pitches for the slider and a new sinker against to begin 2026. Pittsburgh absolutely clobbered those pitches. So in Miami, he shelved the slider and sinker.
The 2023 column in that table tells the rest of the story. Before surgery, Williamson was a fastball-cutter pitcher. Those two pitches accounted for 67% of everything he threw, and the fastball is actually faster now than it was pre-TJ. Back then, he also used the changeup 16.5% of the time and the slider only 10.2%. He didn't throw a sinker at all. The Pittsburgh start looks like a pitcher who came back from Tommy John and tried to add pitches he didn't have before. The Miami start looks like a pitcher who remembered what worked.
But his improved performance wasn't simply a matter of throwing different pitches. What he actually did was much harder than that — through hard work and tenacity, Williamson figured out how to throw his best pitches better.
The Changeup
Stuff+ measures the raw quality of a pitch (velocity, movement, spin) on a scale where 100 is league average. Location+ measures how well the pitch was located. Pitching+ combines the two and adds sequencing context. All three use 100 as the baseline. Above 100 is above average; below 100 is below average.
On March 31, Williamson's changeup graded out at an 81 Stuff+, a 64 Location+, and a 45 Pitching+. A Pitching+ of 45 means the pitch was actively hurting him every time he threw it. It wasn't just bad, it was a liability. And he was throwing it 12.8% of the time.
On April 6, the same pitch graded at 100 Stuff+, 114 Location+, and 113 Pitching+. He went from a changeup that was actively hurting him to an above-average pitch, and he doubled its usage to 28%.
| Changeup | vs Pittsburgh | vs Miami | Change |
|---|---|---|---|
| Stuff+ | 81 | 100 | +23.5% |
| Location+ | 64 | 114 | +78.1% |
| Pitching+ | 45 | 113 | +151.1% |
| Usage | 12.8% | 28.0% | +15.2 |
I think the Stuff+ jump from 81 to 100 is the part that matters most for his long-term outlook. Stuff+ captures the physical quality of the pitch, the movement and the speed differential. That went from genuinely below average to right at the league mean. The location improvement is encouraging, but location fluctuates more from start to start. Stuff doesn't change as easily. If his changeup's movement has stabilized at a 100 Stuff+, that's a pitch he can build a plan around.
For a lefty coming back from Tommy John, trusting the changeup is as much about confidence as it is about mechanics. The surgery changes the feel of the grip. The arm has to learn to decelerate the same way again. It's one thing to throw a changeup in a bullpen session. It's another to go to it with runners on in a game when the last time you did, the Pirates hit it into the seats. Doubling the usage tells me Williamson went in with a plan and trusted it.
The Cutter
This one's a quieter story. The cutter's Stuff+ actually dropped slightly between starts, from 97.7 to 90.7. The pitch didn't get nastier.
It got more precise.
Location+ jumped from 97.5 to 148.7, and Pitching+ followed it from 109 to 157. A Location+ of 148 is elite. Even in a single-game sample, that's a pitcher painting. He spotted that pitch exactly where he wanted it, and it showed. A cutter located on the hands or off the back hip of a right-handed hitter produces weak contact even when the pitch itself isn't special. That's what happened. He also bumped usage from 20% to 28%, making the cutter and changeup a roughly equal pair at the top of his arsenal.
| Cutter | vs Pittsburgh | vs Miami | Change |
|---|---|---|---|
| Stuff+ | 97.7 | 90.7 | −7.2% |
| Location+ | 97.5 | 148.7 | +52.5% |
| Pitching+ | 109 | 157 | +44.0% |
| Usage | 20.2% | 28.0% | +7.8 |
I think the cutter improvement says something about Williamson's command returning. Tommy John recovery is about the whole arm, and the cutter needs the wrist to be exactly right at the point of release. You can't aim a cutter. You have to trust the release point, and a pitcher who's two starts into a comeback is still calibrating. The March 31 cutter was decent. The April 6 cutter was placed with intent.
Where the Ball Went
The result of the mix change shows up most clearly in the batted-ball data.
| Metric | vs Pittsburgh | vs Miami | Change |
|---|---|---|---|
| Avg. launch angle | 30.8° | 6.5° | −24.3° |
| Ground ball rate | 5.9% | 52.6% | +46.7 |
| Fly ball rate | 64.7% | 31.6% | −33.1 |
| Barrels | 3 | 0 | −3 |
| Home runs | 3 | 0 | −3 |
An average launch angle of 30.8 degrees is a parade of fly balls. That's what the Pirates did to Williamson on March 31: they lifted everything. Only one of his 17 balls in play was a ground ball. Three were barrels, the kind of contact that almost always results in extra-base hits or home runs.
On April 6, the average launch angle dropped to 6.5 degrees. Ten of 19 balls in play were ground balls. The Marlins didn't even manage to barrel the ball once against him.
We can also look at his induced average exit velocity numbers. Oddly enough, the Marlins' EV was higher than the Pirates'. The hard-hit rate rose too, from 41.2% to 47.4%.
But this all together and you get a who thrived at inducing hard ground balls for outs in Miami.
That's what changeups and cutters do. They don't make batters swing softer, they change where the bat meets the ball. A batter who was geared up for a 93-mph fastball and gets an 86-mph changeup instead is going to hit the top of the ball. The exit velocity might still be 95 mph, but if the launch angle is negative four degrees, that's a routine grounder to short. A barrel requires both high exit velocity and a launch angle in the 26-to-30-degree window. Take away the angle and the exit velocity doesn't matter.
I should also acknowledge the opponent. Pittsburgh's Opening Day lineup is a better group of hitters than what Miami put out on April 6. The Marlins are rebuilding, and a weaker lineup changes the degree of difficulty. The pitch-quality grades account for count and sequencing, but they don't adjust for the talent of the opposing lineup. Some portion of the improvement is Williamson facing easier at-bats. How much is hard to say from two starts.
What to Watch
Two starts is nothing. A pitcher who throws well in one game against the Marlins has not proven anything about who he is for the rest of the season. The sample is tiny, and the opponent was one of the weakest lineups in the National League. And Williamson could very well be sent to AAA Louisville when other starting pitchers come back from the IL.
But the changes between these two starts are structural and incredibly promising. He didn't just get lucky with sequencing. He changed what he threw and where he threw it. The pitch-quality grades confirm the improvement: overall Pitching+ went from 96.7 to 114.7. CSW% (called strikes plus whiffs per pitch) went from 22.3% to 32.3%. That's elite territory. Batters chased more of his pitches outside the zone (33.9% vs. 27.1%) and made contact on those chases far less often (57.9% vs. 87.5%). Those are the numbers of a pitcher who was more deceptive, not just more fortunate.
The number to watch next time out is changeup usage. If it stays near 28% and the Pitching+ holds above 100, the April 6 start is the new baseline. If it drops back toward 12% and the location grades collapse, the Pirates outings was closer to where he is right now.
A pitcher coming back from Tommy John, two starts into the season, with one good game and one bad one, doesn't resolve the question of who Brandon Williamson is in 2026. But the data from his well earned Win in Miami suggests he's on the right path.
