The development we see from pitchers is rarely in a straight line. Whenever something gets better, we usually see something else fall off at least slightly. I think at least some of that has to do with how many facets of the game we can evaluate and how much they all tend to be in at least some state of flux. This idea serves as a reminder to not be discouraged when it seems like a pitcher may have taken a step backward. Even if the underlying numbers are looking rough, that’s not necessarily an indication that a pitcher has gotten worse.
With that in mind, we’re looking at Tanner Bibee today. A pitcher who had a phenomenal rookie season, a somewhat expected regression to the mean in his second campaign, and has come out of the gate a bit slow but with some noticeable changes to how he operates. I believe Bibee has made a give-and-take move that nets neutral in the short term but sets him up for future success. Let’s take a look at what Bibee is doing this year, and how it differs from previous seasons.
The Current Mix
As of now, Bibee is still leading with his 4-seam fastball as the primary pitch. His doing this has always confounded me because it’s not a particularly great fastball. It’s at about league-average velocity, and he releases the ball a bit higher than the average pitcher, but its movement can cause problems for him. It doesn’t have enough spin efficiency (85%) to maximize movement, but he also isn’t cutting it to get a better shape. The result is a fastball that moves in the direction you would expect it to given his release, but with substantially less actual movement. This does not bode well for its ability to miss bats or induce bad contact. He got away with it in his rookie year, but the pitch looked a bit worse in 2024 and it got hammered.
This year, it has even less movement than it did previously, being down about 160 RPMs from last season. That’s a concerning amount, but the result probably isn’t much worse than what last year’s edition of his 4-seam looked like. For what it’s worth, his fastball saw a change in the last month of last season that was pretty similar to what we’re seeing now. It performed well in that small sample, though I’m not sure how much stock to put into that.
In the past, he’s lost IVB throughout the season. Be it due to fatigue, changing baseballs, the weather, mechanical changes, etc. But it hasn’t bounced back this year. This may be due to the small sample of pitches, in which he hasn’t thrown a single fastball below the middle of the zone, which leads to lower IVB numbers. The performance of his fastball made up a lot of the difference between his year 1 and year 2 results, so how the new version fares is something to monitor.
His go-to secondary has always been his “cutter”, which is functionally more of a slider. He started throwing it a bit harder in 2024 and has retained that shape this year. It’s an excellent pitch that should both miss bats and draw bad contact provided it’s in good locations. He does still have a pitch to fill the role his old cutter might have in his current arsenal, with a truer sweeper picking up the slack as a strikeout pitch against righties. Both of his breaking balls are excellent, though the cutter has been hit well in the small sample so far this year. I don’t expect that to last, he’s always had good feel for locating it. The few punished mistakes probably aren’t a sign of anything.
The first big change we’re covering here, Bibee has finally made a sinker a real part of his arsenal. He toyed around with one last season but didn’t throw it enough to remark on. Now he’s throwing it regularly to right-handed hitters, and it’s a good sinker too!
He maintains his delivery across his fastballs well enough, and it’s separated from his 4-seam by ~6” IVB and ~10” HB. It gets an exceptional amount of seam-shifted wake which adds to its deception as its initial spin direction looks very similar to his 4-seam. He hasn’t figured out how to run it in on their hands yet, mostly just throwing it in the zone as much as he can. As he throws it more and his command of it develops, this could be a game-changer for him against righties.
Lastly, Bibee throws a pretty good changeup. He doesn’t kill much of its rise, but it fades a lot with 16.7” of arm-side movement, and it’s got velocity separation that would make an old-school pitcher proud. 81.7 mph changeups compared to a 94.1 mph fastball is a huge gap by today’s standards. It’s always been one of his better offerings.
What’s The Difference?
So, we’ve covered his new sinker. The remaining changes lie in how he’s using his pitches, who he’s using them against, and the absence of one he’s always had.
The most obvious one is that his curveball is nowhere to be found this year. While it was always more of a once-in-a-while pitch that he would toss in looking for called strikes, I’m surprised to see it gone. It’s especially surprising given his overall usage. He’s fully bought into pitching to the platoon advantages his stuff has.
(Table via BaseballSavant)
The 4-seam is the only pitch to be thrown more than four times to both handednesses of hitter. The changeup is lefty-exclusive, the cutter, sweeper, and sinker are all righty-exclusive. When looking at this, I’m confused about the shelving of the curveball. He’s only throwing two pitches to lefties now, and the curve would probably be the next best option if he doesn’t want to throw cutters to them.
He hasn’t run into issues against lefties yet this season, but I’m not convinced that working just fastball-changeup to them is going to be sustainable. As good as that changeup is, something’s going to have to give. Either the cutter has to find its way into these matchups (most probable), the curveball will have to come back (possible), or he could debut a new gyro breaker mid-season (unlikely but would be awesome).
What Does All This Mean?
In short, Bibee has adjusted his arsenal in a way that should help him better handle same-handed hitters but might leave him worse off against lefties. In adjusting his pitch usage to being nearly exclusively to the hitters they should fare better against, he may have inadvertently created a problem for his platoon splits.
Pitching development is a complicated thing. I don’t know that I fully agree with all of the choices Bibee made this offseason. I love the new sinker, it’s something I’ve wanted him to try for a while. But the way he’s handling left-handed hitters just doesn’t make sense to me at all. I don’t mean to imply I know better, I’m not that egotistical. The Guardians don’t often steer their pitchers in the wrong direction, there’s certainly good logic behind what they’re doing with Bibee here even if I’m not on board with it yet. I would love to be proven wrong and watch as Bibee’s two-pitch approach to lefties works for him all year. If that doesn’t happen though, I would expect further arsenal evolution from him. As previously mentioned, he has other options if this winds up falling apart.
This leaves Bibee in an interesting spot. The new way of doing things yielded odd results through his first three starts. He cruised through 5.2 unremarkable innings against the Royals in his first outing. Then he racked up 16 whiffs against the Angels but also gave up four homers. After that he faced the Royals again and couldn’t get anyone to chase, driving up his walk rate though he didn’t allow any of them to score. It’s probably too soon to make substantial changes on the fly. I’d expect maybe some small modifications over the next few outings if anything. That said, Bibee is a noted tinkerer, if the scuffling goes on too long, I’d expect him to switch things up eventually.
Writing this, it feels a bit out of order as I’ve already talked about what he could do differently from this point. It’s mostly just partially reverting to what he was doing last year, which feels reductive. This is assuming there even needs to be a change made. Maybe I’m not following my own advice and being overly critical of a few substandard outings in which he tried something new, suggesting he already needs to change something against lefties before they’ve even burned him for the new approach.
The big thing from here is to watch what it is that Bibee’s doing on the mound, that’s more important than the box scores. As his command returns to normal, so should his results. Again, I think overall the changes he’s made should be about neutral, and he’ll be similarly effective to how he was last season. The good news is there are clear paths to further improvement should they be necessary.
A Tangent On Pitchers’ Progress Being Tricky
(If you’re only here to get an opinion about Bibee, you can comfortably skip this part, the rest of this article is more of a rant about the patience required when evaluating developing pitchers)
This section isn’t data-driven as much as it is just observations I’ve made while studying this subject. Bibee’s changes coming with both positives and negatives is a very regular part of how pitchers grow. Trying new things as a pitcher is difficult and doesn’t always lead to immediate positive results. That new sinker of his, as much as I like it, is probably going to get knocked around a bit if he doesn’t start locating it better. It’s all part of the process. Not every new offering is going to be like Skenes’ splinker and become one of the game’s best pitches immediately upon learning it. The growing pains pitchers experience when they modify their approach can be annoying for fans but it’s often a necessary part of their development.
It’s also not exclusive to new pitches of course. Sometimes a pitcher will have a problem with walking too many hitters, so they make an effort to throw more pitches in the zone, and the walk problem becomes a barrel problem as now they’re missing in the zone instead of way out of it. It’s progress toward the ultimate goal of improved command, but potentially a worse outcome in the meantime. It can also look like a pitcher trying to pitch backward to maximize the value of their best pitches or compensate for a bad fastball, but still struggling as the command of their breaking balls is exposed in the higher usage. A decent chunk of pitching development is throwing things at the wall (usually baseballs) and seeing what sticks. New things, or even the same old things but in different ways, are all going to have their ups and downs.
The point of this rant isn’t so much to educate as it is a request for patience when pitchers are trying to improve. I know it can be frustrating to watch, especially with the idea of “if it wasn’t broke, why did you try to fix it?” floating around when good pitchers make changes. Professional athletes are in a relentless pursuit of excellence, to be the best they can be. For pitchers, more so than most other athletes, that can mean fundamentally changing what it is they do. Little changes can have large effects, but reinventing yourself is a phenomenon almost exclusive to pitching. Those metamorphoses both big and small can be difficult adjustments to make though. Evaluating pitchers can be tough, but not every rough patch is a sign of things going awry. Sometimes it can be the last step toward a big leap of progress.
