The best pitches for Cardinals' starters and relievers in 2023

Baseball Savant has a statistic called "run value". Essentially, this figure measures how good a pitch was for a particular pitcher. It is one of the most comprehensive statistics when looking at the effectiveness of a pitch.

Baseball Savant defines run value as "the run impact of an event based on the runners on base, outs, ball, and strike count". Run value is defined on a per-pitch basis as opposed to a per-plate appearance basis. In theory, pitchers should lean on their best pitches and avoid their weakest pitches. This is a fine line to walk, however, because the more often a hitter sees a pitch, the more comfortable he gets against it.

For context, Adam Wainwright had the absolute worst pitch in baseball last year among qualified pitchers. His sinker had a -23 run value by the end of the season, and he used it 31.4% of the time. Gerrit Cole's 4-seam fastball was the best pitch in baseball according to run value, and he used it 53% of the time.

The St. Louis Cardinals have acquired a plethora of pitchers this offseason. Sonny Gray, Lance Lynn, Kyle Gibson, Andrew Kittredge, and Keynan Middleton are all guaranteed roster spots. Incumbent pitchers such as Miles Mikolas, Steven Matz, Ryan Helsley, Giovanny Gallegos, and JoJo Romero will be returning to the pitching corps in 2024.

There are some pitchers who are on the fringe of making the roster. Matthew Liberatore, Zack Thompson, Nick Robertson, Andre Pallante, Drew Rom, John King, Riley O'Brien, and Ryan Fernandez are all possible bullpen arms. Of these 8 relievers, Andre Pallante's 4-seam fastball graded out as the best with a run value of 18. Conversely, Andre Pallante's slider was the worst pitch out of this collective with a run value of -8. This could be why he's added a death ball this offseason.

Ryan Helsley's best pitch was his slider with a run value of 9. Matthew Liberatore threw only 1 pitch out of 4 with a positive run value, his sinker, and Zack Thompson's curveball was one of the best on the team with a run value of 6.

Let's take a look at the 10 pitchers who are guaranteed a spot on the roster and find out what their best pitches were last year.

Starting Rotation

Sonny Gray: Sweeper

Run value: 19
Usage: 20.4%
Batting average against: .097
# of pitches thrown: 576

Sonny Gray's newly-acquired sweeper was a top-10 pitch in all of baseball last year with a run value of 19. He used it sparingly compared to his other pitches, but its effectiveness was off the charts. Batters hit a meager .097 against the pitch, and he struck out batters at a 53.2% clip when using his sweeper. It averaged a ridiculous 15.6 inches of horizontal movement.

Steven Matz: Sinker

Run value: 8
Usage: 56.1%
Batting average against: .240
# of pitches thrown: 1,046

It makes sense that a pitcher who generates groundballs at an above-average rate would favor his sinker. Steven Matz threw over 1,000 of these pitches last year, and it was his most used pitch. Batters fared pretty well against it with an average of .240, but Matz used it to limit hard contact with an average exit velocity of just 89.6 MPH.

Miles Mikolas: Slider

Run value: 7
Usage: 24.3%
Batting average against: .245
# of pitches thrown: 776

For as ineffective on the whole as Miles Mikolas was last year, his slider was his most effective pitch. He didn't use this pitch to get batters out or generate whiffs, but it was effective at preventing hard contact (88.3 MPH exit velocity). This pitch was Mikolas's third-most frequent offering behind his 4-seamer and his sinker. Outside of his changeup, his sinker was his only pitch with a positive run value.

Kyle Gibson: Sweeper

Run value: 12
Usage: 18.5%
Batting average against: .147
# of pitches thrown: 562

The St. Louis Cardinals targeted pitchers who throw sweepers this offseason. Kyle Gibson increased his usage of his sweeper by over 15% from 2022 to 2023. It so happened to be the best pitch he had last year by a wide margin. Batters were foiled by his sweeper which had over 10 inches of horizontal break. Should Gray continue to lean on his sweeper in 2024, he will experience success on the mound.

Lance Lynn: Changeup

Run value: -1
Usage: 7.0%
Batting average against: .302
# of pitches thrown: 221

After reviewing Lance Lynn's pitch profile using run value, I lost faith in his ability to pitch well next year. Not one of his 7(!!) pitches used last year had a positive run value. His 4-seam fastball, typically his best offering, was his worst pitch according to run value when it used to be his best pitch. Batters smoked Lynn's changeup for a .302 batting average last year, the highest of his pitches. If he can tap into his four-seamer next year, perhaps Lynn can turn back the clock slightly.