So dominant as a rookie last season, Oh has allowed multiple hits in five of six appearances this year. He has been scored upon in four of those outings. In comparison, Oh allowed an earned run in just 12 of 76 games in 2016. His pitches-per-inning average has jumped from 16.4 to 20.3.
Manager Mike Matheny offered a pair of explanations when asked about Oh's inability to boast more clean innings. One, Matheny surmised, could be Oh's workload, which has been inconsistent. With the Cardinals losing nine of their first 12 games, there haven't been a plethora of save opportunities to hand to Oh.
He went six days between his first and second outings of the season, and had another stretch when four days passed without throwing a pitch.
"You're afraid to go out there and throw him an inning when you might need three days in a row with a one-run lead," Matheny said. "[We'll] try to get him enough work and let him kind of lean on that. That guy knows what he's doing. He knows when he needs to pitch. We follow his lead."
Secondly, his slider has been much less effective. Opponents hit .164 and slugged .246 against the pitch last year. Entering Tuesday, those averages were .500 and 1.500, respectively. His whiff rate on the slider has dropped from 26.54 percent to 14.29 percent.
"I see just a little bit with the slider up in the zone, more so than we saw last year," Matheny said. "It's something he's working on to get that down bite instead of the side-to-side. But he's getting better with it."
Of that assessment, Oh, speaking through a translator, responded: "Mike's on point with that. I'm trying to get with the slider, and trying to get the location and command right. That's what I'm working on."
Oh still has managed to convert two of his three save opportunities, and with several of the team's relievers still searching for command, the Cardinals aren't likely to make a closer change right away. But they do hope to soon see signs of things trending in a different direction for the 34-year-old right-hander.
Could getting out of Tuesday's pickle be a step in the right direction?
"That's what I'm hoping," Oh said.