The Athletics made a quick bullpen shuffle Thursday afternoon, claiming left-hander Joe Rock off waivers from the White Sox and sending him straight to Triple-A Las Vegas. To make room on the 40-man roster, right-hander Justin Sterner was transferred to the 60-day injured list.
Rock’s time in Chicago was brief. The White Sox designated him for assignment two days ago after a three-month stay in the organization, and he logged four appearances from June 13-24. In that stretch, he gave up four earned runs over 10 1/3 innings while striking out 12, but the command issues were hard to miss: 11 walks, two hit batters and a wild pitch.
That control trouble is a big reason the underlying numbers looked rougher than the ERA. Rock’s 3.48 mark sat well below his 5.65 SIERA and 6.84 expected ERA, suggesting he was living on thin ice even in a small sample.
The story hasn’t been much prettier in Triple-A, either. Across 32 2/3 innings for the Rays and White Sox’ top affiliates, Rock has posted a 6.89 ERA and an 18.1% walk rate.
There are some positives buried in there - a 28.1% strikeout rate and a 50.6% ground ball rate - but the damage has been too frequent. Opponents are batting .407 on balls in play against him in the minors, a number that’s wildly unsustainable, though it’s only part of the explanation for his struggles.
For Oakland, though, this is a low-risk stash. The A’s bullpen sits 19th in the majors in strikeout rate at 21.6% and 28th in ground ball rate at 38.4%, so Rock at least gives them a depth arm with traits they can use if he settles in.
The issue, as always, is the walks. He was far more manageable in that department in 2024 and 2025, with walk rates of 5.7% and 9.3%, so there’s at least a chance for some positive regression once he gets comfortable.
Sterner’s IL move was no surprise after he had season-ending right knee surgery two days ago. He was solid out of the bullpen last year, turning in 65 innings with a 3.18 ERA and an 18.4% K-BB rate.
He carried that over through his first 34 innings this season before everything unraveled in his final 7 1/3 frames, when he was tagged for 13 earned runs. That late collapse leaves him with an ERA above 6.00 and a rate of 2.32 home runs per nine innings.
He’s expected back when healthy in 2027.
In Other News...
Athletics May Have Found Another Arm Worth Watching In Stockton
Josiah Romeo gave Stockton exactly what a club wants to see from a young arm in late summer: length, control and no runs. The right-hander worked deep into the game to help the Ports beat Visalia 7-2, extending Stocktons winning streak to three and giving the Athletics another low-level pitcher worth tracking as the season winds down.
Romeos outing stood out in a night filled with offense across the system, from Sacramentos 15-11 slugfest with Las Vegas to Midlands shutout of Amarillo. But in Stockton, the more meaningful development was on the mound, where Romeo kept the Rawhide quiet long enough to make the result look comfortable and leave the As with another encouraging data point in the pipeline. [Read more 🡒]
Jacob Lopez Is Giving The Athletics Something They Desperately Needed
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For Oakland, the value goes beyond the present tense. The front office is weighing roster changes and possible call-ups as it looks ahead to a longer runway, including the possibility of being more competitive by 2027. Lopezs emergence gives the Athletics a candidate to factor into those plans, whether as part of the next wave or as a reminder that some internal answers may already be in the building. In a year defined by struggle, that kind of development matters. [Read more 🡒]
As Head To Kansas City With A Rare Chance To Build Momentum
The Athletics head to Kansas City after a week that offered both frustration and a little encouragement, dropping a series to Tampa Bay but taking a divisional set from Texas. For a club still searching for any kind of late-season traction, that split of results matters because it has given Oakland something it has not had often enough lately: a chance to carry one good series into the next.
Kansas City offers a similar setup in that the Royals are also out of playoff contention, which makes this four-game road series less about the standings above than the race to avoid the bottom. Oakland is trying to claw its way up and keep from finishing last in its division, the league, or the sport, and the only way to do that now is to keep stringing together the kind of small runs that have been so hard to find. [Read more 🡒]