The Cubs have talked a lot about how their Pitching Infrastructure, led by Tommy Hottovy and Craig Breslow, provides a competitive advantage on the pitching front.  However the results the past two years have not been especially strong.  There have been a lot of individual success stories, but because of the lack of investment prior to this year there hasn’t been a full pitching staff meant to win games as opposed to a collection of individual pitchers meant to be flipped in July.

2023 is year four since the pitching group within the front office was overhauled.  There’s now been some time to develop pitchers and have them matriculate through the farm.  There have also bee. some significant trade and free agent resources invested in the MLB staff.  The team also, finally, seems to have at least some urgency for raising the W flag more often than not.

Now that we’re roughly 10% into the season, sample sizes are starting to get closer to meaningful.  Particularly on a team-wide level, samples are no longer tiny.  And we’re really seeing how the Cubs are generating the results they’ve gotten to this point.  It’s a nuanced answer, but if you wanted to boil it down into one word that word would be “Sliders.”

The Cubs have had the best staff in baseball utilizing the slider, both in terms of process and results. 

In terms of results, the staff has been +15.3 in Slider Run Value via Pitch Info on Fangraphs.  That’s the top mark in baseball.  This is not just a volume play either, as they’re 12th in MLB in the rate of throwing sliders at 25.3%.  So they’ve derived the most slider value in the sport despite a fairly average rate of usage.

Maybe that’s just luck though?  What about the underlying aspects of the sliders they throw?  We have data on that as well.  Fangraphs has two different models that measure the effectiveness of specific pitches based on the underlying aspects like spin, movement, velocity, etc.  These models also have methods for attempting to measure pitch command as well.  There are nuances to Stuff+ and Pitchingbot, but both have pretty sophisticated math behind them.  The good news is both agree that the Cubs are #1:

• Pitching Bot: #9 in Stuff, #4 in Command, #1 Overall
• Stuff+: #3 in Stuff, #4 in Command, #1 Pitching+

So the story is clear, the Cubs as a staff have good sliders in terms of stuff, though the extent of how good is up for a bit of debate.  What’s not up for debate is an elite level of slider command. 

And they’re doing this up and down the staff.  This isn’t just one or two elite arms.  Wesneski (#10), Taillon (#21), and Steele (#24) are all Top 30 amongst MLB starters this year for Pitching+ with the slider.  Thompson (#14), Adbert (#46), Fulmer (#58), and Rucker (#59) are all Top 60 amongst relievers (for reference, 244 relievers have thrown a slider in a game this year).  There’s potentially more reinforcements on the way.  Javier Assad has a 133 Stuff+ on the slider, but the command isn’t there yet.  Jeremiah Estrada had a 126 when he was up last year.  Bailey Horn purportedly has one of the best sliders in the org.  The list goes on and on.

The sweeper has been one of the stories league-wide this season, and the Cubs are at or near the forefront in terms of implementation.  It’s looking like the Org’s big talk about being one of the smartest pitching orgs in the league is starting to have some evidence backing it up.