Shortly after the conclusion of 2022’s Winter Meetings, the Pale Hose swung a deal that sent former sixth-round pick Kade McClure to San Francisco in exchange for young, embattled reliever Gregory Santos. Three days prior, Santos had been designated for assignment by the Giants after a tumultuous tenure that saw inconsistent results and an 80-game PED suspension.
You’d be forgiven for not remembering that deal, because it did little to raise any eyebrows at the time and was quickly overshadowed by Andrew Benintendi’s mammoth, five-year, $75 million contract just two weeks later.
Santos has taken his relative anonymity in stride this far into 2023, pitching to the tune of a 2.66 ERA in 42 games in his first season with the Sox. His FIP, a stat that neutralizes the inherent randomness of defensive performance, is a couple of ticks lower at 2.44, indicating that his true added value to this White Sox bullpen is greater than his surface-level stats suggest.
Furthermore, Santos is achieving this success without significant help from a reliever’s best friend, the punch out. He averages a little less than one strikeout per inning, which is a slightly below-average mark for relief pitchers in 2023. A quick trip to Santos’ advanced statistics shows exactly why he has been so successful to this point; nobody in the league misses more barrels than he does. Santos is at or near the Top 10th percentile in fastball velocity, walk rate, expected ERA, or chase rate. And his barrel percentage is the best in baseball.
How do you determine “best” in a league of 500 pitchers? Put it this way: Santos has not allowed a single barrel in 2023.
Simply put, Santos’ quality offerings miss a batter’s sweet spot with unparalleled frequency. This can be attributed to a sweeping power slider that, in addition to typically clocking in at a blazing 92 mph, displays well-above-average vertical drop and horizontal movement and grades out as one of the top five pitches in all of Major League Baseball this season. His sinker, which tops out at 100 mph, similarly displays well-above-average vertical drop. Those two pitches in tandem consistently have batters unable to properly square up the baseball, resulting in contact that rarely has a chance to leave the yard. Santos also mixes in a four-seamer and a changeup, both of which are average offerings, but play well off of the two elite primary pitches that he throws interchangeably.
Gregory Santos, Sick 100mph Sinker.— Rob Friedman (@PitchingNinja) July 16, 2023
"With a swing that's gonna be on PitchingNinja..."
[Jason Benetti never misses] pic.twitter.com/gOQJt19x2E
The practical result of Santos’ dominating peripherals is a season in which he leads all White Sox relievers in WAR — and in fact, only Lucas Giolito and Dylan Cease (with more than double the innings) have a higher pitching WAR than the young sinkerballer. To add league-wide context, Santos currently checks in ahead of legendary closer Kenley Jansen and electric Guardians closer Emmanuel Clase in those same terms.
Kade McClure, the former White Sock dealt to the Giants to acquire Santos, has yet to debut in the majors and is currently pitching to a 5.79 ERA in Triple-A. It’s safe to say that this is a trade that, so far, has leaned heavily in the White Sox’s favor, and all indicators point to Santos being able to sustain this level of play in the second half.