The South Korean has now been touched for at least an earned run in each of his three outings this season.

Oh came on in a non-save situation for the second straight time. With the Cardinals trailing 7-3 in the eighth, Oh allowed a two-out double to Bryce Harper, who hammered a 96-mph fastball to left.

Daniel Murphy drove Harper home with a double of his own, as Oh hung an 87-mph slider over the middle of the plate.

Oh got Ryan Zimmerman to line out to center to end the inning.

Oh recorded 19 saves and a 1.92 ERA in 76 appearances last season, after taking over from Trevor Rosenthal as the closer in July.

After another shaky outing, Oh has a 12.27 ERA.

Oh told the St. Louis Post-Dispatch that his feel for off-speed pitches isn't quite as sharp as he'd like it to be.

"Everyone says that you get the feel for the breaking ball when you pitch more," Oh was quoted as saying. "You always get a better feel for it during the season. But the season has already started and right now that would just be another excuse from me."

Oh blew a save in his season debut against the Chicago Cubs on April 2, when Willson Contreras touched him for a game-tying three-run homer in the top of the ninth at Busch Stadium in St. Louis. Oh was credited with the win later when the Cardinals scored the winning run in the bottom of the ninth.

A week later, Oh entered the game against the Cincinnati Reds with the Cardinals down 7-0 in the top of the ninth and gave up a solo shot to Joey Votto.

The second-year big leaguer allowed just five home runs all of last season, 79 2/3 innings in total, and never did so in back-to-back games.

The first home run off Oh last year came on May 25, and he didn't give up his second long ball until July 22. (Yonhap)