Did a midseason reinvention give the White Sox another ace reliever? 

Here's a trivia question to get us started: Over the last seven weeks, which relief pitchers have the highest strikeout rates?

You've probably already thought of a few names. Yep, you're right, Mason Miller (42.9%) is on the list. So is Seattle's Andrés Muñoz (46.7%). It shouldn't be a shock that Ryan Zeferjahn (44.6%) is here, either. But how about the others?

Highest strikeout rates since June 21, RP
Min. 10 IP (232 pitchers)

1. Mason Montgomery (PIT): 56.1%
2. Andrés Muñoz (SEA): 46.7%
3. Ryan Zeferjahn (CHC): 44.6%
4. Mason Miller (SD): 42.9%
5. Samy Natera Jr. (LAA): 41.1%
6. Jonathan Bowlan (PHI): 39.7%
7. Jordan Hicks (CWS): 38.7%

There are a few names that stand out here, but let's focus on Jordan Hicks, who has re-discovered the best version of himself for the feel-good White Sox. Since coming off the injured list in late June after a month-long absence due to a lat strain, Hicks has a 1.17 ERA with a 38.7% strikeout rate in 18 appearances across 16 1/3 innings. He's pitching in high-leverage roles, like on Sunday, when he tossed a scoreless eighth inning to preserve a two-run lead against the Guardians. In that same seven-week span, Chicago's bullpen has the fifth lowest ERA (3.00) in the Majors, and Hicks is a key reason why.

This is not the same pitcher who began his White Sox tenure by posting a 5.60 ERA with a 17.2% strikeout rate in 20 appearances. So, what changed? Let's ask Hicks.

"After coming off rehab, I took my arm slot up a little bit," Hicks said on July 29, after he tossed a scoreless 12th inning in a thrilling 6-5 victory over the Yankees. "Just really started enforcing the four-seam in the zone and playing catch with it. I feel like those two things, really trying to get back to the 2023 version. But I feel like I'm throwing more strikes than back then. Everything is working now."

That's a lot to unpack. Let's dive in.

In 2023, Hicks pitched to a 3.29 ERA (134 ERA+) in 65 appearances out of the bullpen for the Cardinals and the Blue Jays, the latter following a midseason trade. His average fastball velocity -- four-seamer and sinker -- was 100.1 mph, and he delivered the ball from a three-quarters arm slot (40 degrees).

That offseason, the Giants signed Hicks to a four-year deal and promptly converted him to a starting pitcher. Although Hicks showed flashes of promise, the experiment didn't exactly work. It culminated in a disastrous 2025 campaign in which Hicks posted a 6.95 ERA, the highest mark among 287 pitchers to throw at least 60 innings. His strikeout rate (18.5%) dipped to a career low. The White Sox acquired Hicks from the Red Sox in February in a deal that also netted pitching prospect David Sandlin because Chicago was willing to take on most of Hicks' salary.

On March 26, in his first appearance of the season, Hicks allowed three runs and recorded just two outs. What's more important, though, is that he threw his fastball from a low three-quarters slot (29 degrees).

Recall earlier that Hicks said he raised his slot "a little bit." We can both see and quantify that. In his first outing off the IL -- June 21 -- Hicks used a more traditional three-quarters slot (39 degrees).

It's not uncommon for a pitcher to tinker with their arm slot during the season, though any changes are often minor. A difference of just a few degrees isn't noticeable on TV. But raising one's slot by 10° is a massive change, especially in season.

As we might expect, the new arm slot led to different pitch shapes, too.

Let's start with the four-seam fastball, which has assumed an increasingly important role in Hicks' arsenal. Since coming off the IL, Hicks has used his four-seamer 27.3% of the time. He has never used it this often before. He threw 44 four-seamers in July, his second-highest total in a single month in his career -- and that includes his tenure as a starting pitcher, when his pitch counts were up.

In March/April, Hicks' four-seam fastball averaged 9.1 inches of induced vertical break, which reports the amount of "rise" a pitcher creates from how he spins the baseball. That's hardly anything. For context, only one qualified right-hander -- the Royals' Randy Dobnak -- is generating less rise on their four-seamer this season. The average four-seamer from a right-handed pitcher has 15.7 inches of IVB.

Creating "rise" requires backspin, which counteracts the effects of gravity and carries the ball through the zone. Backspin is easier to put on the baseball from a more over-the-top arm angle. On the other hand, a more side-arm slot lends itself to horizontal movement. Since changing his arm angle, Hicks has added nearly five inches of IVB to his fastball -- it's up to 14.5 in. in August -- which allows it to carry better through the zone.

Something similar is happening with his sinker, too: Hicks has added four inches of IVB to the pitch, which now generates 11 inches of vertical movement.

These aren't elite rising fastballs, to be clear. But in changing his arm angle, Hicks has prioritized more vertical movement over horizontal movement, and it's helped turn his season around.

The other factor here is velocity, which Hicks alludes to when saying that he's simply "playing catch" with his four-seamer. Premium velocity has always come easily to him; he burst onto the scene as a rookie in 2018 and promptly threw a pair of 105 mph fastballs within his first few months in the Majors.

But Hicks lost a large chunk of that elite velocity as a starting pitcher, and it took him a while to recoup it. His fastball velocity fell to 94.6 mph -- into the 59th percentile of MLB -- in 2024; even this April, as a reliever, his fastball velocity sat at 98.2 mph.

Since his return from the IL, Hicks has an average fastball velocity (again, we're including four-seamers and sinkers here) of 99.9 mph. Only six pitchers (min. 150 fastballs) throw harder. In July, his average fastball velo was 100.1 mph; that was his fastest single-month average fastball velocity since June 2023 -- there's that year again, the one that Hicks wanted to get back to.

Put this all together, and you get a pair of fastballs that are suddenly very difficult to hit.

Opposition against Hicks' fastballs

• Pre-IL (20 games): .304 BA / .413 SLG / 8.4% whiff rate
• Post-IL (21 games): .205 BA / .273 SLG / 19.6% whiff rate

The last thing that Hicks mentioned is pounding the zone, and he's right about that, too. In the first month of the season, he found the zone just 51.3% of the time with his fastballs. In July, his fastball zone rate was 58.2%.

He's playing catch and challenging the opposition to hit his best stuff.

And for the better part of the past two months, a revamped Hicks is winning over and over again.

MLB.com senior reporter Scott Merkin contributed to the reporting of this story.