Charting Rookie Pitchers: End-of-Season Review

Midseason, I charted the rookie crop of pitchers using a z-composite score. As the first full season for many of these pitchers wraps up, let’s come back to them to see how they fared and what this means for fantasy value moving into 2027.

To roughly go over the composite again, I weighted the z-score across five categories I personally think tell us a lot about the ability of pitchers early in their career and, hopefully, serve as a foundation for future performance. I weighted K-BB% and Stuff+ at both 25%. K-BB%, to me, is the clearest indicator of any pitcher’s underlying performance: how often do they miss bats and how rarely do they issue walks. Stuff+, evaluating the movement and velocity of their pitches, is a more stable indicator than Location+ and can be a more durable indicator for long-term success in the league, where the ability to locate the ball can come with experience.

At 20% each, the score is CSW% and z-contact%. CSW% blends called strikes with swinging strikes across the whole zone, measuring how well a pitcher wins. Z-contact% is specifically about contact rate on swings against pitches in the zone. A pitcher can rack up called strikes without necessarily limiting in-zone contact when hitters do swing. But once hitters start swinging more, if they are making contact, things can go bad. That’s what caused Trevor McDonald to regress over the course of the season.

Lastly, at 10% is HardHit%. I contemplated splitting this 10% with ground-ball rate, which I did not include initially due to the noisiness of the numbers early in the season, but given the rankings and score didn’t change significantly, I opted for continuity of the composite.

Each metric is converted to a z-score relative to the rookie class itself, not the full population of qualified MLB starters, so a positive score means above average for this group specifically. That choice gives clearer visual separation on the chart and keeps the comparisons meaningful within the class rather than diluted against the league at large.

One thing I noticed when building the composites was that the scores are more volatile for pitchers with fewer innings. A rookie sitting at 55-100 IP has more of his season riding on any single start than one at 150+ IP, so his relative standing can move more than his underlying stuff actually changed. This in part explains why Early, Painter and Imai were able to add so much from their mid-season scores, but it doesn’t invalidate their performances.

CSW% in particular is incredibly tight across this specific rookie class this year, so even a modest month-to-month change in CSW% can swing a score more than I would like. I ended up favoring continuity, as the actual positions of the pitchers in relation to each other didn’t change that much, just the differences from the earlier iteration, but it’s something to remember in future exercises.

The composite is plotted against xERA on the scatter chart.

Two Set Apart

From the mid-season rankings, there were a few major movers, and I expect this trend to continue into next year. Payton Tolle and Logan Henderson were so incredible in 2026 that they have actually skewed the scores quite a bit for the rest, as they set the ceiling so high. Despite leading the mid-season score with 1.140, Tolle was the second biggest riser by the end of the year, building on an already stellar first half. Tolle was able to improve in multiple categories, but the biggest gain was bringing his HardHit% from 37% to 34.5%, while also possessing the best Stuff+.

Henderson maintained his impressive season, and as Jack Dorfman noted in his article, this consistency gives him an incredible floor. Check out that piece for a great breakdown on his success. While he wasn’t able to raise his ceiling as high as Tolle did in the second half, he still possesses the best K-BB% and Z-Contact% of the group. The gap is still notable from the profiles below between the two at this stage, particularly in contact suppression.

However, the gap between Henderson and the following tier of rookies is significantly bigger than the gap between him and Tolle. A remarkable season from the Brewer, who at times was even able to go toe-to-toe with his teammate and likely Cy Young winner, Misiorowski, will put him in the upper tiers of fantasy starters in 2027.

End of 2026 Breakouts Primed for 2027

Following strong ends to the year, both Andrew Painter and Walbert Ureña are primed for big 2027s. After Tolle, they were the only two pitchers to have increased the composite score by more than .400 points.

Andrew Painter really struggled early in the season, and despite his high profile, he was one of the most disappointing rookies from the composite score. His struggles were rooted in his fastball; despite an average velocity of 96 mph, he couldn’t miss enough bats. The profile of his fastball, I think, gives promise; it has good shape given his release height and decent ride. His below-average extension, given his height, means it does not get on bats as quickly as you would expect with a tall pitcher. Fastball spin has climbed steadily from 2202 rpm in April to 2401 rpm in September, whiff rate on the pitch went from 9.6% to 22.4% over that same stretch, and IVB ticked up in his last two starts (17.0 to 18.1 inches). Some mechanical changes may be warranted in the winter to keep improving on his four-seamer, as contact rates remained high even with the improvements.

Where his real improvements have come from is his off-speed pitches. Painter’s midseason pitch swap is a clean success story. Through May and June, the split-finger was a real part of his mix, running as high as 28% usage in a given start, but the results didn’t hold up: -1 run value on the season, a .411 xwOBA against, and a .532 slugging percentage allowed.

Since returning in August, the split-finger hasn’t shown up. In its place, the changeup was introduced as a new pitch, with usage climbing from about 16% in August to 30% by late September following its introduction after his return to the majors, and the results justify it: +6 run value (best pitch in the arsenal), .172 xwOBA, 38.4% whiff rate. At 90.5 mph with 4.9 inches of induced vertical break and 12.5 inches of horizontal break, with a 110-116 proStuff+ range in his last two starts, this will be a massive weapon in 2027 to go along with his above-average sweeper.

Across his final two starts, the changeup and sweeper again gave a glimpse into Painter’s sky-high ceiling. The changeup drew whiffs on 40 and then 50 percent of swings, the second outing pairing that with a .168 xwOBA and a 65 grade (116 proStuff+, 142 proPitch+). The sweeper matched it swing for swing, missing bats on six of seven against the Mets before settling into a .280 xwOBA and a 60 grade against Milwaukee. The fastball also showed a real positive sign. Spin hit a season-high 2443 rpm against the Mets, season average 2318, with 18 inches of IVB, both ahead of where the pitch sat most of the year.

What still hasn’t caught up is contact. The fastball carried a .388 xwOBA against Milwaukee, and the Mets start saw 13 batted balls with six hard-hit at a 90.6 mph average exit velocity. Three walks against Milwaukee, his most in a start in September, also highlighted persistent command issues. These final two starts explain much of his rise in the composite over the final months, but also show where he still needs to improve to be a fantasy asset.

Walbert Ureña has been one of my favorite pitchers to track this year. His stuff, particularly on certain pitches, is just so ridiculous; the talent is abundant, something about that turbo-sinker/changeup combination. But that wild unpredictability, while fun to watch, meant he was never a realistic fantasy option this season, at least. But he ended up being one of the biggest pitching surprise stories in 2026, popping up in nearly every pitcher chart I made, and to now see him as one of the most improved rookies this year, I will look forward to taking the punt in 2027 drafts. Perhaps to my peril.

Looking at his pitch mix, it is clear where he found his identity this season. From August, usage of the sinker and changeup, his two best pitches, climbed, with the sweeper mixed in start-to-start and especially the four-seam declined. He started the year on a pitch-mix rollercoaster, his usage swinging with increasing disparity week to week, but settled as Ureña and the Angels gained clarity on how to use his skill set. Throw your best pitches, that tunnel off of each other.

Ureña’s sinker still currently grades out as negative run value for the season, with 39.6% HardHit%, 17.8% whiff; as with Ureña’s profile, it was more a location issue than a stuff issue; he just wasn’t able to throw it enough for strikes, with a 36% in-zone rate in April. But he was able to improve this as the season went on, increasing the sinker’s in-zone rate to 58% by September; GB% climbed from roughly 54% to 65%, with HardHit% down from 54% to 37% over the same stretch.

These are all encouraging signs given his groundball profile. And while the negative run value may still alarm some, I think looking at it within the context of the tunnel with his changeup is important. As we can see with the paired pitches visualization, there is not much that separates the two in terms of their relationship to one another. So while his changeup has a run value of 18, this is inflated, borrowing results from the sinker’s setup work, which doesn’t get the statistical credit it deserves. Whereas the true run value for each pitch may lie somewhere between -1 and 18 for both pitches. But this more defined idea of who Ureña is as a pitcher, built off of these pitches, will make him intriguing for fantasy in 2027.

Given the offseason, I may look into further deep dives into some of the rookies’ outlooks for 2027, as there are some more interesting names that did not even appear in the mid-season edition.