2025 Player Reviews: Austin Cox

Left-handed pitcher Austin Cox bounced onto and off of the Atlanta Braves’ roster for much of the summer of 2025, but his most memorable outing was also one of the most bizarre games in all of MLB this past season. A forgettable stretch of games brought an end to his big-league run in 2025, though he ended up with oddly good peripherals anyway.

A Macon, GA native, Cox was a fifth round draft choice in 2018 by the Kansas City Royals out of Mercer University. He made his major league debut with the Royals in 2023 and after bouncing around in the minor league system for a couple of years, Cox signed with Atlanta on May 5, a day after the Royals let him go.

What were the expectations?

Cox went directly to Triple-A when signed; at the time, he seemed more like speculative, organizational bullpen depth rather than the guy that would actually serve as very real bullpen depth for much of the summer.

Cox had 0.5 fWAR in 35 2/3 innings for the Royals back in 2023, but that came with a 103/87/111 line (ERA-/FIP/xFIP-), so they didn’t see fit to give him another chance. That made sense, too, because Cox was getting absolutely drilled in Triple-A, with an xFIP above 5.00 at that level in 2024, and then good peripherals but an insane home run rate before he was released in 2025. Basically, expectations for a replacement-level swingman at best.

All in all, Cox had kind of a weird season. He made one start and 19 relief appearances for the Stripers after Atlanta signed him, putting up a 4.45 FIP but 5.25 xFIP, as he struggled to strike anyone out with his new team but still walked a fair bit of guys.

With Atlanta, though, he ended up posting reasonable-enough strikeout and walk rates, but got absolutely blasted by the longball, with a third of fly balls against him leaving the yard. The result was that in 21 1/3 innings, Cox posted a bizarre 210 ERA-, 184 FIP-, and… a perfectly-fine-for-a-low-leverage-reliever 97 xFIP-. In total, he gave up nine homers while having 64 outs recorded while pitching, which is a really, really bad rate of homers to happen to anyone. It’s also how he ended up with -0.6 fWAR in just those 21 1/3 innings. Woof.

That total came across what felt like a bazillion roster moves. He was recalled to the big-league team four times, and three of those stints were 11 days or shorter. He finally stayed up for much of August, but that didn’t go quite so well and we’ll get to that in a bit.

Well, overall, the peripherals were good. On top of that, Cox actually excelled through his first nine outings, with a 15/3 K/BB ratio and just a single homer allowed in 11 2/3 innings. (That’s a 73/61/59 line!) That stretch included a situation where Spencer Strider got scratched from the Bristol Motor Speedway game on August 2, giving Cox his only start of the year.

In conditions that normally wouldn’t have been played, Cox only got through one-third of an inning before the downpour finally reached a level that led to the game being suspended. When the game resumed on Sunday, Hurston Waldrep to made his season debut tossed 5.2 innings of fantastic “relief.”

Beyond the big-league peripherals, it’s also possible to at least say some nice things about his arsenal on paper. His non-fastball pitches (slider, curve, split) were pretty effective, and even his fastball (along with his slider/cutter thing, and maybe his split) have a nice, or at least decent, shape.

His best outing of the season came on August 6, when he was asked to throw the eighth with a two-run lead against the Marlins, and had a 1-2-3 inning with a groundout and then back-to-back strikeouts. Here’s Cox striking out Colton Cowser to keep the game tied in an earlier appearance, back when he was dealing, in what his highest-WPA play of the season.

Something really funny about the season Cox had was that his highest-WPA play came during the game in which he lost the most WPA overall. I wonder how often that happens…

The thing is, the reason why most arms bounce around the waiver wire and ride the Triple-A shuttle generally tends to be command, and Cox… did not show good command. Things got especially dire in his last four outings of the season, where Cox was basically just asked to eat innings, and got lit up like the facade of a suburban house that’s really, really into Halloween. In his final 9 2/3 innings of the season, he had a poor 7/4 K/BB ratio but, more importantly, somehow gave up eight homers. Five of those came on his four-seamer, which ended the season with a horrific .458 xwOBA-against.

This is such a weirdly sad way to have your worst WPA play of the season, it’s a necessary inclusion here:

Cox is still on Atlanta’s 40-man roster, but chances are he loses his spot as the Braves work to transform their roster this offseason. Maybe he sticks around, or maybe he gets cut at the same time other teams are trimming their rosters, clears waivers, and sticks around on a minor league deal to serve as depth again.

Still, Cox had good major league peripherals despite not being a high-strikeout guy. It’s just that those eight home runs in his last four games sunk his season. He projects as pretty replacement level-ish right now, but that’s not really an impediment to the Braves or someone else giving him a spring training invite anyway. He could also head overseas, though maybe that happens after he’s out of option years and no longer carries the ever-desirable roster flexibility that an option year allows.