On December 22nd, 2022, the White Sox acquired relief pitcher Gregory Santos from the San Francisco Giants in exchange for minor league pitcher Kade McClure. There wasn’t much known about Gregory Santos at the time this trade was made. He totaled 5.2 innings pitched at the major league across 2 seasons with the Giants.

Santos, began his career with the Boston Red Sox but was traded to the Bay area in the Eduardo Nunez trade at the trade deadline during the 2017 season. Not much was known about Santos but the Giants gave him a shot, largely because of his power arm. During the 2021 season, Santos would be suspended for 80 games due to testing positive for a Performing Enhancing Drug. The following season he would make only 2 appearances for the Giants, and would then be DFA’d (Designated for Assignment).

But in 2023, Santos has found a home in the Southside of Chicago and he’s been nothing short of exceptional.

Santos has appeared in 27 games this season, pitching to an impressive 2.05 ERA over 30.2 innings. Santos’s pitch repertoire is primarily a sinker & a slider. This combo of pitches gives him a 55 % groundball rate (MLB average is 42%) His sinker averages 99 miles per hour (mph) and at times goes well over triple digits. Opponents are hitting .297 against it with a slugging percentage (SLG) of .406. When looking at BaseballSavants expected stats (expected stats look at the quality of the contact of each batted ball and assign it a hit probability based on other comparable balls in play), Santos has been unlucky. The xBA is .264 and the xSLG is .328. Hitters are having a hard time putting quality contact against his sinker.

As for his slider, it has been one of the best this year. Opponents are hitting .192 and slugging a measly .212. It sits at 91 mph but at moments has gone up to 95 mph. It is Santos’s main swing and miss pitch, sitting at a 35% whiff rate.

Gregory Santos has been a revelation for the White Sox. His ability to command the zone paired with his great stuff, its clear why hitters are struggling the way they are.