The Cardinals bullpen has been weak so far this season, and the regression of Oh has been a big reason why

In the Cardinals’ quest for a .500 record, it’s important to remember how we got here. One of the major problems in the early season has been the bullpen. So far, the Cardinals bullpen is bottom 5 in ERA and batting average against.

It’s easy to forget that the bullpen was supposed to be a major strength this season. Brett Cecil, and Kevin Siegrist were all supposed to be major pieces in a dominant bullpen. They have both faltered to start the year.

Of course, the linchpin is Seung hwan Oh, the second year closer out of Korea who was dominant in his rookie year. So far, he’s been anything but.

Oh has only pitched in 9 games this season, but he’s been struggling. His WHIP is well over 1.5, his ERA is over 5.00 and his ERA+ is under 100. To put his performance in perspective, Oh has allowed 14 hits through 9 appearances.

Last season, Oh allowed his 14th hit in appearance 26, in late May. To say he has regressed a bit this season is putting it lightly. Now, with almost of month of Cardinals baseball under our belts, we can start to look at Oh’s performance and determine if last season was a fluke or if he’s been a victim of some baseball luck gremlins to start 2017.

As usual, we’ll be relying on Fan Graphs batted ball percentages, as they give a good insight into whether a pitcher is struggling due to luck or lack of skill. However, I want to make note that these statistics are heavily influenced by sample size. It’s dangerous to draw any conclusions from small changes at this point in the season, so we’re going to use them as more of a guide and less of a definition of his performance.

Already too old?

Let’s start with the most obvious criticism of Oh. Last year he debuted in the majors as a rookie at 32 years old, making this his age 33 season. You know who else is 33? Jim Johnson, noted bad relief pitcher. Through this rigorous statistical analysis I have concluded that Oh is simply too old to be a good pitcher anymore.

Of course, I jest. There is nothing indicating that Oh is slowing due to old age. All of his pitches have the same velocity as they did last year, and he’s not getting any less movement from what the eye test tells us.

The stuff is definitely there. Another thing that can indicate aging is a player moving away from their fastballs and relying more heavily on their other pitches. Oh does not seem to be doing that at this point in the season.

The joke that all of the Cardinals are getting old is a pretty easy one to make. However, of all factors that could contribute to Oh’s slow start, age is certainly not one of them.

Bad luck or something worse?

It does feel like we’ve used the “bad luck” mantra a lot around here at the beginning of the season. I regret to inform you the bad luck is at it again. Up to this point in the season Oh has some very unsustainable batted ball percentages that I anticipate dropping as the season goes on. Right now, his GB/FB is .63 while last season it was right around 1. Most of Oh’s poor stats can be attributed to the fact that he’s getting very few ground balls.

It’s true that Oh’s line drive percentage and fly ball percentage is up by a bit, but we’re not looking for small 5-7 percentage point changes. We’re looking for major discrepancies. Here’s one: the league average ground ball percentage (GB%) is around 44%, last year Oh had a GB% of 40.0%.

This year? 28.6%.

That number is impossibly low, and consider the fact that line drives and fly balls lead to 1.26 runs per out and .13 runs per out while ground balls lead to .05 runs out. Pitchers need to cause ground balls to prevent runs, and that’s just not happening right now for Oh.

Another ridiculous stat is Oh’s infield hit percentage, which is calculated as infield hits/ground ball.  Last season it was at 13.5%.Right now, it’s at a sky high 30%. This means that even when Oh does get a ground ball, its winding up as an infield hit anyways.

Infield hits are not really under Oh’s control, and if anything they indicate poor defense behind him more than poor pitching. These ground ball and infield hit rates are a major factor in Oh’s astronomical .364 BABip, a tell tale sign of poor luck.


Oh will not have a season as good as last season. But that was expected. Between his unknown rookie status and his low HR/FB rate, Oh was already the benefactor of luck last season.

However, this season the pendulum has swung the other way. Oh has had an abysmal time getting ground balls. Even when he does, they turn into hits 30% of the time.

Whether or not Oh’s pitching style is causing him to miss out on ground balls remains to be seen, but no pitcher goes from a 40% ground ball rate to a 30% ground ball rate in the span of a season. Oh may not be as dominant as he was his rookie year, but he will continue to be an above average closer once he starts getting balls to hit the ground.

Photo captured by Jeff Curry – USA Today Sports