Joe Rock's stint on the South Side didn't last long. The 26-year-old lefty was designated for assignment by the White Sox just three months after Chicago acquired him from Tampa Bay, and now he's changing organizations again — this time landing with the Athletics.
MLB Trade Rumors broke the news that Oakland claimed Rock off waivers, and the corresponding roster move tells you exactly what kind of asset the A's think they're getting: he's being optioned straight to Triple-A Las Vegas, not stashed on the big-league staff. To make room on the 40-man, Oakland shifted right-hander Justin Sterner to the 60-day injured list following knee surgery.
Rock's path to this point has been a whirlwind. Colorado took the 6-foot-6 southpaw in the second round of the 2021 draft out of Ohio University, then flipped him to Tampa Bay in March 2024 for outfielder Greg Jones. He got his first real major-league look with the Rays in 2025 and looked sharp doing it — a 2.35 ERA and 11 strikeouts across 7 2/3 innings out of the bullpen. That performance made him interesting enough that the White Sox sent infield prospect Oliver Dunn to Tampa Bay to get him in a mid-May trade.
The problem has always been the same one: strikes. In four appearances with Chicago between June 13-24, Rock posted a respectable-looking 3.48 ERA over 10 1/3 innings with 12 strikeouts, but he also walked 11 hitters, hit two more, and uncorked a wild pitch. The advanced metrics were uglier still, with a SIERA north of 5.5 signaling the ERA wouldn't hold. His Triple-A numbers backed that up — a 6.89 ERA and an 18.1% walk rate in 32 2/3 innings, even with elite swing-and-miss stuff behind it.
That's the trade-off that's made Rock a hot potato all year: the strikeout rate (28.1%) and ground-ball rate (over 50%) are the kind of numbers teams covet from a lefty his size, but you can't get outs walking the ballpark. He posted much tighter walk rates in 2024 and 2025, so there's recent evidence the command isn't permanently broken — which is presumably the bet Oakland's pro scouting department is making by taking a flier here.
For now, this is pure organizational depth for the A's, not a September call-up plan. Rock will try to sort himself out in Las Vegas, and if the walks come back down to earth, a team that's churned through pitching all year could have another shot at finding a useful piece for cheap.