Recent baseball pitcher changes: Bubba Chandler, Kyle Harrison, and more

I’m not a coder by nature, so I will admit to using AI for help with the coding, but the design was something I had been thinking about for a while. I took some of my preferred indicators that could be used to spot shifts in performance and added them to a database. That included results-stats like exit velocity and barrel rate, or velocity increases and usage changes for pitchers. It also included process-based stats like swing rate, chase rate, pull air rate, two-strike usage for pitchers, etc., and it also included biomechanical indicators like arm angle for pitchers or batting stance changes for hitters. I then had the database set up to flag any meaningful changes across segments of 50 plate appearances (or about three starts for a starting pitcher).

What that led to was me having an evolving database of hitters and pitchers who were doing new things that deserved my attention.

Now, some of it was not as useful. You can have pitchers who stop using a pitch for two starts because of hitter handedness, or you can have a hitter who has a surge in barrel rate without anything else changing in their process or swing mechanics. However, by having something flag these names for me, I’m able to dig into each name and see if there is something tangible happening under the hood.

As a result, I can now share some of those changes with you.

Andrew Painter - SP, Phillies (Arm Angle Change, Four-Seam Movement, Changeup Shape)

I wrote about Andrew Painter

Bubba Chandler registered a 40% whiff rate on his 4-seam fastball last night. That’s around 18% better than his season average with the pitch (22.3%). — Jason Shetler (@Jason_Shetler)

Clay Holmes - Cubs (Arm Angle Change, New Cutter Shape)

Since coming to the Cubs, Holmes has used his cutter 16% of the time (34.3% to righties), which could be because he seems to have morphed the pitch into more of a slider shape, down to about 85.4 mph and with six inches more drop. He's using it 26% of the time in two-strike counts, and it does have a really solid 40% PutAway Rate in those situations, so you have to wonder if he will start going to it more often. My initial thought is that he's using it to offset some velocity loss and movement issues on his sinker. In his last two starts, Holmes has thrown the cutter about 60% of the time early in counts to righties, which is about the same as he's used his sinker. His sinker has averaged 92.2 mph with the Cubs but was almost 94 mph with the Mets before his injury. His arm angle has also dropped, which has led to some shape changes on the sinker and could be why both his zone rate and strike rate on it to righties have decreased since returning.

Holmes still has a 3.51 ERA and 1.14 WHIP in his six starts with the Cubs, but his 15% strikeout rate brings nothing to the table for fantasy, and it's clear that he is still adjusting to pitching after fracturing his leg. Pitching is so much about balance and weight transfer that it would make sense that Holmes would still be compensating for the injury despite returning to the mound for almost two months.

Chris Bassitt - Orioles (Curve Usage, Cutter Velocity)

Since coming back from injury, Bassitt has a 4.34 ERA, 1.48 WHIP, and 19% strikeout rate, so this is not a player you're really running to get, but I did want to note that his cutter has averaged 90.5 mph and has been over 91 mph in two of his last three starts. He averaged just 89.6 mph on it before the injury, so that is a noteworthy change. The pitch also has a 14% swinging strike rate since returning after posting a 10% mark before the injury. Another shift has been his curveball usage. He's used it 46.2% of the time in two-strike counts since coming back, which is way up from 34% before the injury. His curveball also has a 7% increase in PutAway Rate because he's doing a better job of keeping it low in the zone. The curve has always arguably been Bassitt's best pitch, so using it more in two-strike counts makes some sense. I could see him emerging as a deeper league streamer down the stretch.