Spring is here! It’s been fun to watch live baseball again. In this piece, we’ll rip through some names that have stood out.
I’m also excited to get you my 1-30 system pitching development ranks next week (~ Wednesday). It’s heavily based on a survey I sent to 50+ MLB coaches/executives. Stay tuned!
There are several instances this spring where I’ve seen data that doesn’t line up with my gut. The four-seam shapes of Bubba Chandler and Mitch Keller looked awful in their first starts and then fine in their second starts. Richard Fitts had a bunch more movement on his four-seamer and sweeper on Feb 25. Rays prospect Ty Johnson was throwing a four-seamer with 3” more vertical break than last year, without a change in release or spin.
I’m not an expert with stuff models or adjusting for environment, but I’d guess wind is playing a big factor in some of these games (and maybe just bad data). Baseball analyst Vivienne Pelletier mentioned that crosswinds can affect a pitch by up to 4”. When there aren’t second and third decks for seating at a stadium, the wind fingerprint changes. And all these spring parks are considerably different than MLB parks in structure. Noted baseball thrower Robert Stock also found that air density affects on Stuff+.
In short, if I see a large jump in movement without a change in slot, release, or spin, I’m assuming nothing has changed with the pitcher. Just assume they look like their 2025 regular-season shapes until 2026 data in MLB parks proves us wrong.
Feb 23: 2 IP, H, 2 BB, 2 KFeb 28: 3 IP, H, BB, 4 K
Let’s start with one of the worst pitchers in baseball last season. I expect the Nationals to considerably cut their four-seam and sinker usage. As a team, they threw 55% fastball last season (combined 4S and SK). That was the most in MLB. So far in spring, they’ve thrown just 41.7% fastballs, second lowest behind the Marlins. There will be clearer examples of Nationals pitchers successfully cutting usage when we get regular-season data, but Irvin intrigues me because his projections are so bad (~5.00 ERA in ~20 starts).
Irvin has thrown just 40% four-seam and sinker in spring after throwing 54% last season. Against lefties, his curveball has led his mix with 30% usage, while his cutter has followed at 25%. Against righties, he’s tripled his short slider usage to 23% from the 2025 regular season. The idea here is to cut back four-seam usage, a pitch that allowed a 16% barrel rate to righties and 12% to lefties.