I took all pitch data from 2021-2025 and pulled all two-pitch sequences where a strikeout could have occurred. There was a total of 1,068,858 combos Here is a table that shows the 5 best and worst sequences overall, w/out any filtering, along with their K%

This thread is a summary of my full article on pitch sequencing, which can be found here: https://gregnieskens.substack....

After filtering out RPs and Double-Ups, we are left with these as the best and worst sequences based on K% to same and opposite-handed hitters. Notes: -more CB and SP to opposite-handed hitters, as they are generally platoon neutral - more SW and SL to same-handed hitters

Initial takeaways: 1) SW -> SL is the best two-pitch sequence and continues trending up It has a near 25% K% against same-sided hitters and 21% to opposite-handed hitters. This trend goes hand-in-hand with SW usage trends, but the combo itself is still underutilized (cont.)

2) Throw Fewer FF in 2-strike counts The best sequence involving a FF is FF -> SL, which sits 25th out of 59 combos in K% (min 1000 combos) When you set a velo threshold of 95+, the K% increases across the board If you are throwing Fastballs with 2K, you better be throwing gas

3) Is SW-> SP an underrated sequence? The combo has the highest K% amongst all combos with more than 500 samples. Could it be the start of a trend? It makes sense from a hitter perspective: big breaking ball setup ➡️ see potential FB out of hand and you swing over the top of SP

Let's look at sequences on an individual scale now. Here are the best and worst sequences from 2021-2025 with the same filters as above 18/20 combos incorporate some form of FB... shows the importance of having a good fastball when you get to 2K Bad fastballs = avoid w 2K

Keeping it just this season, here are the best and worst sequences for Starting Pitchers in 2025:

Looking into the usages can be helpful too. Let's look at Brayan Bello, whose SI -> CH combo had the highest K% out of any sequence since '21 Bello basically cut out the sequence in '25, and he saw a 3.3% drop in K%. Coincidence or not, he should bump the usage of it in '26

Here is a list of guys that I think need to either increase or decrease their usage of certain combos to potentially see an uptick in K% heading into 2026 (regardless of batter hand)

It would be a bad thread if I did not mention the art of tunneling when sequencing. If a pitcher sees success on poorly graded pitches, it could be a result of good tunneling within an arsenal. Below are 3 SP that generate Ks on poorly graded pitches after good setup pitches:

Let's use Eovaldi's FF/CB combo to visualize this. Here is a video I put together that shows the setup pitch, the kill pitch, and an overlay of the two. At Trout's decision point, the pitches look identical. He sees FB again and swings right over the top of the CB. Really nasty

It can also be easy to tell when a pitch does not tunnel well with a setup pitch. Eury Perez has an elite FF with a below-average CB His 10% K% on his FF → CB combo in '25 shows that it may be easier to read out of the hand when thrown right after a FB

In the end, sequencing is just a small part of the puzzle. While fun to dive into, I do not believe there is a "right answer". It is so individualized that it is tough to have too many general takeaways. A good combo that works for three pitchers may not work for the fourth

My final thoughts: 1) Some guys can sequence to get better results out of poor pitches, like Kelly or Bradish. For most, the best way to get results is to simply improve their stuff Better pitches are harder to hit, regardless of sequence or deception ⬇️

2) Velocity is still king when it comes to FBs. If you are throwing FB in 2K counts, you better be throwing 95+, or at the very least have outlier movement/deception Ks ⬆️ as the velo ⬆️, and a good fastball generally makes your secondary offerings more competitive Throw hard!

3) Understanding why a pitch may not perform well when thrown after another is an important part of the puzzle. Ex: Freddy Peralta, his FF is elite after his CB, but his CH after his FF is bad. Understanding the why behind this can be helpful, and it will differ between pitchers

4) SW sequences are rising in popularity, and the hitters have not adjusted yet. I believe usage will continue to increase and will be incredibly effective until that adjustment is made 5) An increase in SP usage as an effective platoon neutral pitch is on the horizon End of 🧵

Thanks to @TJStats for providing the stuff grades and to @RBunikiewicz and @DMstats30 for their helpful suggestions

@SkinnyGraphs @isaacgroffman @isaacgroffman I still wish Jacob DeGrom was a Met 😔

@SkinnyGraphs I think @PitchingNinja would really enjoy this thread!

@SkinnyGraphs I thought these shadows were fake. DeGrom throwing fuzzballs out there with a Death Star like shadow. Hitting is hard

@SkinnyGraphs Is there a physically harder task in the world than hitting Jacob deGrom with those shadows