Starting Pitcher June 2025 Stuff+ Risers & Fallers

Pitchers seemingly change during the season more often than hitters. By change, I mean their talent level fluctuates as their velocity bounces around, they tinker with their pitch mix, mechanics, etc. So it could be insightful to look at recent trends to help decide whether a pitcher is establishing a new performance baseline. So let’s look at June Stuff+ marks for all qualified pitchers in the month. Whose Stuff+ grade has risen most and whose has fallen? Let’s find out.

First, I’ll begin with the June Stuff+ risers.

Brayan Bello got a late start to the season due to injury, first making his debut on April 22. For the season, the underlying skills have been weak, but the combination of career bests in BABIP and LOB% have helped push his ERA below 4.00 for the first time. Through the end of May, his Stuff+ sat well below previous marks, which resulted in a disappointing strikeout rate. In June, he has regained most of the lost stuff he first suffered last year, as his Stuff+ has jumped back over 100. That has corresponded with a rebound in strikeout rate. Since the grounders continue to be there, he’ now back to a matchup play in shallower mixed leagues, though do watch for luck metric regression as his ERA might still rise toward his SIERA/xERA marks.

Tanner Bibee’s 101 Stuff+ earlier in the season wasn’t significantly below where he landed during his first two seasons. Yet, his strikeout rate had plummeted to sub-20%, which was massively disappointing after two straight mid-20% marks. In June, he’s really turned things around as the quality of his stuff has surged and his strikeout rate has been back over 20%. Surprisingly, that June strikeout rate still remains below what he has posted in 2023 and 2024, even with the big jump in Stuff+ to meaningfully higher than those two seasons. I would imagine the strikeouts will come, so this is still good news for worried Bibee owners.

Charlie Morton?! He made five starts at the beginning of the season to disastrous results and was subsequently moved to the bullpen. He then returned to the rotation in late May and has suddenly rediscovered his peak skills. His fastball velocity has been better, which has likely helped, while both his curveball and changeup has experienced Stuff+ spikes. On the season, his ERA remains an inflated 5.64, which has concealed the massive improvement he’s seen this month. Obviously, there’s no way he maintains a 30%+ strikeout rate, but perhaps the 41-year-old isn’t actually done yet as an effective pitcher and fantasy contributor like it seemed earlier.

Max Fried’s early season Stuff+ was already a career best for him, and he’s amped it up even higher in June. All of his pitches sport Stuff+ marks over 100! What’s crazy is that even with the elite Stuff+, his strikeout rate is right in line with his career. Furthermore, the June bump hasn’t resulted in as high a strikeout rate as you would expect from a pitcher sporting a 116 Stuff+. He’s been a start during his first season with the Yankees, but don’t ignore the career best BABIP and better than average HR/FB and LOB% marks. His SIERA and xERA marks are both significantly above his actual ERA in the low-to-mid 3.00 range, so his rest of season expectations really shouldn’t differ much from his preseason solely based on his current ERA. Of course, if the improved Stuff+ gets converted into strikeouts, now we’re talking one of the top fantasy pitchers in baseball.

The sample size for Jacob Lopez is relatively small, but it’s fascinating to see those strikeout rates given the weak Stuff+ marks. How does one manage a 36.8% strikeout rate with just a 94 Stuff+?! The real improvement in June has come from his slider, which has consistently recorded a Stuff+ of at least 102 in his four June Starts. Still that was the only above average pitch and the second highest Stuff+ he recorded from all his pitches during any of his June starts was just 93. So I’m not entirely sure how he’s generating a double digit SwStk% from every one of his pitches (except his rarely used sinker) or has posted a near 30% strikeout rate. As an extreme flyballer in a home run happy home park, he needs to keep up those strikeouts to avoid suffering from acute gopheritis and inflating his ERA. I just don’t know how he’s managing to record those strikeouts with seemingly week stuff.

Sheesh, Ryan Pepiot has nearly doubled his strikeout rate in June with an absurd 37.9% mark, but he still posted an excellent Stuff+ even before this month. What’s weird as his June merely brought his season strikeout rate in line with his projected total. Pepiot gained nearly a mile per hour on his fastball last year and he has maintained that this year, which has made his fastball significantly better according to Stuff+. Oddly, his strikeout rate hasn’t moved and his SwStk% is actually lower than the past two years. Oh, and he hasn’t been getting called strikes at past rates either. He has overperformed his ERA estimators so there’s some likely ERA regression in the future, but I feel like he should be capable of posting a strikeout rate well above his season mark so far.

Man, Grant Holmes is another name who is seemingly flummoxing Stuff+. He’s got just a 91 mark for the season, with an improved 95 mark in June, and yet his strikeout rate in both period is far better than you would expect based on the Stuff+. How do these guys do it?! Both he and Lopez have generated a better than average SwStk%, despite well below average stuff, and have converted those whiffs into boatloads of strikeouts. One might guess that his location must be strong so he’s generating those strikeouts in a craftier way, a la Greg Maddux. Yet, his Location+ is exactly average at 100, so I’m baffled. It’s anyone’s guess what Holmes does the rest of the way.

Now let’s flip over to the June Stuff+ fallers.

After missing out on a rotation spot at the beginning of the season, Hayden Birdsong transitioned from the bullpen to make his first start of the season on May 20. So most of his early season innings came from the bullpen, which makes it understandable that his stuff declined. That said, this is a pretty big decline, as he went to featuring well above average stuff in the bullpen to below average stuff as a starter. It’s worked out so far though as the skills have been respectable, as he has posted a 3.99 ERA/3.84 xFIP as a starter. However, his slider has been real weak as a starter, failing to even reach a 100 Stuff+ over his six starts, after making seven relief appearances with a 101+ slider Stuff+ mark. His fastball velocity was initially unaffected, but he was down below 95 MPH on average with the pitch during his last two starts for his two lowest velocities of the season. That’s expected though, but interesting to see the sudden dropoff after his velocity was good his first four starts. It’s something to monitor.

Jameson Taillon’s Stuff+ went from nearly league average to well below in June, and his strikeout rate has fallen to a dangerous level. He has also lost some fastball velocity, as in each of his June starts, he has averaged less than his season mark. Don’t forget that his velocity first dropped significantly last year and has failed to rebound this season, so it might be difficult to even get back to a 20% strikeout rate. Luckily, he has consistently posted elite Location+ marks, which has kept his walk rate down and potentially suppressed his BABIP to maintain a respectable ERA.

Woah, I was not expecting to see Tarik Skubal’s name here! I also had no idea he has posted just a 22.5% strikeout rate over three June starts. Should owners be worried? Ehh, his season strikeout rate is still the second highest of his career, so it’s okay if he doesn’t strike out 35% of opposing batters every game! Even his reduced Stuff+ is elite. There is something worth watching though — both his four-seam and sinker velocity. In his last start, he was down 1.1 MPH on his four-seamer compared to his season average, marking his lowest velocity of the year, and he was down 0.9 MPH and 1.2 MPH on his sinker over his last two starts compared to his season average, both of which were also his lowest velocities of the season. This could be nothing, but also understand that Skubal became the elite pitcher he has thanks in part to fastball velocity spikes first experienced in 2023.

Wowzers, it’s fun to see Mike Burrows’ Stuff+ drop, while his strikeout rate more than doubled. The sample sizes here are small as the pre-June period comprised just 8.1 innings. According to Stuff+, Burrows owns two above average secondaries in his slider and changeup, but his fastball is poor, extremely so. That’s real surprising given its above average velocity. How hard is it to fix a 95 MPH fastball? Perhaps there’s potential here if that happens, but he shouldn’t be on radars until the pitch rates better.

It’s pretty crazy that Emerson Hancock finds himself on this list even while posting just an 89 Stuff+ earlier in the season. How much lower can it go?! The answer…down to 84. I almost talked myself into buying Hancock on draft day as he had flashed increased velocity during the spring. He has even maintained that, throwing his fastball 1.4 MPH faster this year. Yet, the pitch still stinks with an 83 Stuff+, which is actually lower than last year! His slider has significantly improved, but every other pitch is worse than last year, along with his season Stuff+. If you gain 1.4 MPH with your fastball and still sport weak quality stuff with a sub-20% strikeout rate, what else can you do?!

Despite a mid-90s fastball and above average slider, Bryan Woo hasn’t been much of a strikeout guy since his 2023 debut. In June, the strikeouts dried up even further amid worse quality stuff. His four-seam velocity was down during his last two starts, though he has suffered dips earlier this year and rebounded the following game, so it might be nothing. Woo’s calling card has been his control as he has posted microscopic walk rates and sports 110 Location+ marks these past two seasons. As long as that skill remains, then he could get away with an averageish or below strikeout rate, but it definitely hurts his fantasy value.

Landen Roupp has posted some huge strikeout rates in the minors, but it hasn’t translated yet to the Majors, as he sports just a 21.3% career mark so far. Those strikeouts have deteriorated even further in June as his stuff has declined. His sinker velocity was down below his season average in three of four starts this month, though the pitch’s Stuff+ mark hasn’t been affected. His curveball had gone missing though, sporting Stuff+ marks of between just 90 and 96 during his first three June starts (versus a 104 season mark), before rebounding back to 105 during his last start. He’s a tough sell the rest of the way as his SwStk% sits in single digits, his walk rate is nearly double digits, and the strikeout rate just hasn’t been as strong as hoped.

Woah, Zach Eflin’s ERA has skyrocketed over the last two starts as he has allowed 13 runs over just eight innings. Was it a stuff problem those last two starts? Well, from an absolute perspective, sure. But his stuff hasn’t really been good all season, aside from one start he managed a 102 Stuff+ mark, the only one the score has been above 97. From a relative perspective, Eflin has featured weak stuff all season long for the most part and he was doing just fine until the recent blowups. Eflin still owns elite control with a low walk rate and strong Location+. He’ll probably still earn some value in AL-Only leagues the rest of the way as his absurd 19.2% HR/FB rate improves, but the strikeout rate trend is scary, reducing his chances of earning value in anything shallower.