The two pitches that swept the Cardinals offseason acquisitions

For the last few years, the St. Louis Cardinals have been behind the curve when it comes to keeping up with the rest of the league. They were behind when using sabermetrics, and they were late to the party when targeting pitchers who strike batters outs. Most recently, the Cardinals were slow to adjust to pitchers and organizations on a new pitch: the sweeper.

The St. Louis Cardinals acquired nine pitchers this offseason. Of those nine, three are penned into the rotation, and at least one will be in the bullpen. Sonny Gray, Lance Lynn, and Kyle Gibson will all be in the rotation, while at least Andrew Kittredge and possibly Nick Robertson and Riley O'Brien will be in the bullpen.

There are some similarities between the sub-categories of these pitchers; Kittredge, Robertson, Victor Santos, Ryan Fernandez, and Riley O'Brien all have connections to the Cardinals' newest front-office member: Chaim Bloom. Additionally, many of these players feature either a sweeper or a sinker as their primary or best offering.

Riley O'Brien, and Andrew Kittredge both use their sinkers as their primary pitches, and Sonny Gray Kyle Gibson, Nick Robertson, and Lance Lynn feature their sweepers as their go-to pitch. It is clear when evaluating the team's acquisitions this offseason that the sweeper and sinker were two pitches the Cardinals wanted to improve upon from last year.

In 2023, only four Cardinals pitchers threw a sweeper, and only Drew VerHagen threw it with any success. His 31.1% usage rate made it his most used pitch. VerHagen was eighth in all of baseball in run value on his sweeper, and batters hit a measly .128 against the pitch. VerHagen had a modest 35.8% K rate on this offering. The Cardinals missed their chance to resign VerHagen. Casey Lawrence, Jake Woodford, and Drew Rom also threw a sweeper to various degrees, but not one of those pitchers had a positive run value on the pitch.

The sinker was a much more common pitch for Cardinals hurlers in 2023; twelve different pitchers threw a sinker, and players like Steven Matz, Jake Woodford, John King, and Dakota Hudson used it as their primary pitch. For as common as the pitch was in St. Louis, it was just as ineffective when looking at run value. Steven Matz threw the pitch 56.1% of the time for a +8 run value, but his sinker was the only one with positive results on the staff. Batters hit only .240 against it, and Matz limited hard contact, as the average exit velocity against his sinker was only 89.6 MPH.

Adding pitchers who feature sweepers and sinkers seemed to be a focus for John Mozeliak this offseason. Let's take a look at the pitchers added who use sweepers and sinkers often.

Sweeper

A quick primer on the sweeper is probably necessary. A sweeper is similar to a traditional slider pitch. The primary difference is that a sweeper has almost double the horizontal movement of a slider while sacrificing some velocity. Shohei Ohtani's sweeper had nearly fifteen inches of horizontal break while his slider had only eight inches of horizontal break last year. His sweeper also ran 2-3 MPH slower than his slider.

Our very own Adam Wainwright broke down the pitch during a broadcast last year. I have also included a video of one of the best sweepers last year that was thrown by Mitch Keller as an example.

Of the various pitchers the Cardinals added this offseason, Sonny Gray, Kyle Gibson, Lance Lynn, and Nick Robertson all use a sweeper. While Lynn's isn't his primary pitch, he did add it this last year. According to run value on Baseball Savant, Sonny Gray's and Kyle Gibson's sweepers ranked first and third, respectively, in effectiveness in 2023 across Major League Baseball. Gray allowed a .097 batting average with a 53.2% K rate on the pitch; Gibson allowed batters to hit .147 against his sweeper with a 40.6% K rate. Sonny Gray's sweeper "swept" nearly fifteen inches horizontally and averaged 84.3 MPH; Gibson's had less break and velocity, but he was excellent at commanding it down and in against lefties and down and away against righties.

Nick Robertson's slider is dubbed as so on Baseball Savant, but its horizontal break (14.6 inches) and its velocity (83.3 MPH) lead me to think that this slider is more than likely an undiagnosed sweeper. Robertson's slider/sweeper was his best pitch last year.

Drew VerHagen had the eighth-best run value on his sweeper last year in baseball, and the Cardinals let him walk this offseason. Justin Lawrence of the Colorado Rockies had the second-best sweeper according to run value. He is rumored to be a trade candidate this offseason. Jordan Hicks also had a dominant sweeper, but he has since signed with the San Francisco Giants.

As an aside, Cardinals' reliever Andre Pallante, in addition to his "death ball", has added a sweeper in hopes of improving his effectiveness against right-handed batters. Hopefully, his sweeper replaces his slider, the worst pitch in his arsenal according to run value by Baseball Savant. Nineteen inches of horizontal break is ridiculous!