With two months in the books, I found some improving pitchers who could be available on the waiver wire. I used xFIP to filter the pitchers, which uses strikeouts, walks and groundball rate to create a predictive ERA estimator.
To refine my search, I took starters with at least 20 innings pitched in both April and May and found those who saw their xFIP drop and are rostered in fewer than 85 percent of NFBC RotoWire Online Championship leagues (a 12-team league with a 30-man roster).
Here are the 17 starters who made the cut.
| Name | April xFIP | May xFIP | Improvement | NFBC OC Roster% |
|---|---|---|---|---|
| Jack Flaherty | 5.87 | 3.48 | -2.39 | 46% |
| Matthew Liberatore | 4.95 | 3.00 | -1.95 | 26% |
| Martin Perez | 5.02 | 3.84 | -1.18 | 11% |
| Grant Holmes | 4.56 | 3.55 | -1.02 | 63% |
| Slade Cecconi | 4.76 | 3.85 | -0.92 | 3% |
| Noah Cameron | 4.30 | 3.47 | -0.83 | 49% |
| Andre Pallante | 4.56 | 3.77 | -0.78 | 6% |
| Jacob Lopez | 6.41 | 5.65 | -0.76 | 4% |
| Luis Severino | 4.30 | 3.66 | -0.64 | 13% |
| Sean Burke | 4.61 | 4.04 | -0.57 | 73% |
| Eury Perez | 4.38 | 3.87 | -0.51 | 67% |
| Tyler Mahle | 4.16 | 3.88 | -0.28 | 7% |
| Walker Buehler | 3.99 | 3.84 | -0.15 | 3% |
| Dustin May | 4.12 | 4.06 | -0.05 | 83% |
| Aaron Nola | 3.65 | 3.60 | -0.05 | 76% |
| Jeffrey Springs | 4.25 | 4.22 | -0.02 | 63% |
| Janson Junk | 4.15 | 4.13 | -0.02 | 14% |
Here is a look at some of the biggest movers.
Jack Flaherty: Most of Flaherty's improvement comes from dropping his walk rate from 7.8 BB/9 to 2.6 BB/9 (with a corresponding drop in ball percentage from 44 percent to 35). It didn't hurt
With two months in the books, I found some improving pitchers who could be available on the waiver wire. I used xFIP to filter the pitchers, which uses strikeouts, walks and groundball rate to create a predictive ERA estimator.
To refine my search, I took starters with at least 20 innings pitched in both April and May and found those who saw their xFIP drop and are rostered in fewer than 85 percent of NFBC RotoWire Online Championship leagues (a 12-team league with a 30-man roster).
Here are the 17 starters who made the cut.
| Name | April xFIP | May xFIP | Improvement | NFBC OC Roster% |
|---|---|---|---|---|
| Jack Flaherty | 5.87 | 3.48 | -2.39 | 46% |
| Matthew Liberatore | 4.95 | 3.00 | -1.95 | 26% |
| Martin Perez | 5.02 | 3.84 | -1.18 | 11% |
| Grant Holmes | 4.56 | 3.55 | -1.02 | 63% |
| Slade Cecconi | 4.76 | 3.85 | -0.92 | 3% |
| Noah Cameron | 4.30 | 3.47 | -0.83 | 49% |
| Andre Pallante | 4.56 | 3.77 | -0.78 | 6% |
| Jacob Lopez | 6.41 | 5.65 | -0.76 | 4% |
| Luis Severino | 4.30 | 3.66 | -0.64 | 13% |
| Sean Burke | 4.61 | 4.04 | -0.57 | 73% |
| Eury Perez | 4.38 | 3.87 | -0.51 | 67% |
| Tyler Mahle | 4.16 | 3.88 | -0.28 | 7% |
| Walker Buehler | 3.99 | 3.84 | -0.15 | 3% |
| Dustin May | 4.12 | 4.06 | -0.05 | 83% |
| Aaron Nola | 3.65 | 3.60 | -0.05 | 76% |
| Jeffrey Springs | 4.25 | 4.22 | -0.02 | 63% |
| Janson Junk | 4.15 | 4.13 | -0.02 | 14% |
Here is a look at some of the biggest movers.
Jack Flaherty: Most of Flaherty's improvement comes from dropping his walk rate from 7.8 BB/9 to 2.6 BB/9 (with a corresponding drop in ball percentage from 44 percent to 35). It didn't hurt that his strikeout rate also went from 10.0 K/9 to 11.9 K/9. In May, he effectively abandoned his sinker (two percent usage) and changeup (one percent usage).
The ratio damage is done with Flaherty, as seen by his overall 5.31 ERA and 1.60 WHIP. And those only looking at May stats will see similar results (6.26 ERA, 1.50 WHIP) because he was unlucky (.372 BABIP, 50 percent strand rate).
For many pitchers, the fastest way to improve is to throw more strikes. Sounds simple, but it holds so many pitchers back (see Bubba Chandler).
Matthew Liberatore: Liberatore nearly doubled his strikeout rate, going from 5.6 K/9 to 10.8 K/9. He made a couple of improvements. He leaned this his curve (10 percent usage to 21 percent, 11 percent swinging strike rate) and cutter (two percent usage to six percent, 12 percent swinging strike rate). Additionally, he threw his fastballs harder, with his four-seamer and sinker up both up ~0.5 mph.
In all fairness, I think his overall 8.3 K/9 and 3.3 BB/9 are good baselines going forward, which puts him as a 4.00 ERA arm, an improvement on his career 4.59 ERA.
Martin Perez: The 35-year-old saw improvements by striking out more batters (6.0 K/9 to 8.9) and generating more groundballs (42 percent groundball rate to 48 percent). Sadly, I can't find a major change with his pitches. His fastball velocities are steady. He's throwing fewer cutters and sinkers and more four-seamers and changeups, but each change is a very minor one. He is attacking the strike zone more, with his zone rate up from 48 percent to 53 percent.
Overall, I don't see a change to buy into from a guy with a career 4.36 ERA.
Grant Holmes: Holmes's improvement came from increasing his strikeout rate from 7.0 K/9 to 10.2 K/9. There have been no positive changes to his repertoire, with his fastball velocity down 0.5 to 1.0 mph. It could be that he faced weaker competition in May.
The increased strikeouts are a positive, but if Holmes transitions into being a steady fantasy contributor, he needs to cut into his 4.0 BB/9 and 1.33 WHIP.
Slade Cecconi: SLADE (doubles as an American Gladiator) cut his walk rate from 3.9 BB/9 down to 2.0 BB/9, with his strikeouts and groundballs staying constant.
Here is a good way to see if the changes will stick. Go to the player's Player Graphs page on FanGraphs, select By Game, select their last few season (2023 to 2026 in this case, enter six games to represent his May starts, and finally select Walk Rate (BB/9). Here is the graph:
While his six-game walk rate is down to a season low, he's seen his walk rate be lower in previous seasons and then jump back up. While I expect some upward regression at some point, I hope he can go on a nice multi-game run of limiting walks like he did to end 2025.
Noah Cameron: Cameron saw improvement in all three categories:
Stat | April | May |
|---|---|---|
K/9 | 8.0 | 8.6 |
BB/9 | 3.1 | 2.6 |
GB% | 30% | 47% |
The one red flag is his release point being all over the place. Here are his per-game horizontal and vertical release points.
Neither one is close to last season, and they are not steady. During a game, the variation can be worse, with his horizontal release point differing by a foot and a half.
It would be nice to see his release point get closer to his 2025 level.
Andre Pallante: Most of Pallante's gains are from dropping his walk rate from 4.1 BB/9 to 2.7 BB/9 while showing a small bump up in groundball rate (from 50 percent to 55 percent). To get there, he's throwing his slider (16 percent swinging strike rate) more while adding about 1 mph in fastball velocity.
Also, he is trusting his stuff and attacking the strike zone. His zone rate is up from 48 percent to 51 percent, and his ball rate is down from 39 percent to 33 percent. The gains are being hidden by a 4.73 ERA in May because of a .321 BABIP and 1.4 HR/9. Sneaky add.
