When you think of White Sox rookies, names like Colson Montgomery, Shane Smith, and Kyle Teel probably come to mind first, and for good reason.

Montgomery erupted with 21 home runs in just 71 games. Smith transformed from a virtually unknown Rule 5 draft pick into the team’s lone All-Star. Meanwhile, Teel posted an impressive .833 OPS in the second half, ranking among the top offensive catchers in baseball.

But perhaps the most overlooked contributor was rookie Mike Vasil, who quietly emerged as the team’s unsung hero. His 2.9 WAR ranked second among White Sox rookies, trailing only Montgomery’s 3.3 mark.

Vasil was claimed off waivers from Tampa Bay on March 23 and wasted no time making an impact. He logged 101 innings, the most by any reliever in the majors, and delivered not just quantity, but quality as well.

In 47 appearances, he posted a 2.50 ERA while limiting opponents to a .204 batting average. He also proved to be effective in a variety of roles, making four starts as an opener, while also recording three holds and four saves. His efforts helped stabilize a White Sox bullpen that logged more innings than any team in baseball.

Despite a relatively low 19.4% strikeout rate, Vasil remained effective thanks to a strong ground-ball rate. With a ground-ball rate just north of 50%, Vasil ranked in the top 15% of MLB pitchers and limited opponents to a .238 average. His ability to induce weak contact helped mask a troubling 12.3% walk rate.

Vasil’s six-pitch mix includes a 94 mph sinker that posted a Run Value of +7 — a metric that measures how much each pitch affects an opponent’s chances of scoring. His changeup also proved particularly effective, with opponents hitting just .158 off of it.

Weak contact was a theme for Vasil all season as he ranked in the top half of the MLB in both opponent hard-hit percentage and barrel percentage.

Vasil credited much of his success to a Batman mask hanging in his locker, which he was seen sporting several times in the dugout this season. While Vasil is a fan of the Dark Knight, he also used the mask as motivation for a dual identity when his ultracompetitive nature comes out on the field.

On the field, he’s fiery,  often showing emotion after escaping jams or recording big outs for the White Sox. Off the field, manager Will Venable calls the 25-year-old a vocal leader who helps keep the clubhouse loose.

That intensity was on full display during the second game of a July 11 doubleheader against the Guardians. Vasil entered in a tie game in the ninth inning and threw a perfect 1-2-3 frame to help push the game into extra innings. In the 10th, he loaded the bases with two walks but escaped unscathed when Bryan Rocchio grounded out to second. Vasil stormed off the mound yelling, “I’m him!”

He wasn’t done yet. In the 11th, he once again found himself in a bases-loaded jam but induced a 6-4-3 double play off Kyle Mazardo to end the inning. He walked off the mound still screaming, embracing catcher Kyle Teel as he returned to the dugout. His three shutout innings were an escape even Houdini would envy and helped the White Sox stay in position to win the game in the bottom of the 11th.

With his first MLB season under his belt, Vasil looks like a key piece of the White Sox rebuild as they continue working to establish a winning culture.