How does the St. Louis Cardinals rotation compare?

Over the years I have found that perspective helps to assess the performance of the St. Louis Cardinals. Some stats have perspective built in, such as the plus and minus stats that measure a player against the league as a whole with 100 being average. Others don’t have perspective built in and require us to provide our own perspective.

As you know, the St. Louis rotation has been bad this year. For the most part, the bad pitching has been below expectations. Even the pitchers that we had every right to expect to be bad have pitched worse than we thought they would.

But just how bad have the Cardinals in the rotation pitched?

I sent out a tweet with the ERA for each Cardinals starter. A follower replied by asking what the league average was. I looked up the MLB average ERA for starters and sent it in reply. I regretted doing that because my preference has always been to compare National League pitchers to National League pitchers because the DH makes things different enough that it creates a flaw when comparing American Leaguers to National Leaguers.

I put together the below table to help illustrate how each individual Cardinal compares to the National League starting pitcher average (NL SP in blue) as well as the St. Louis starting pitcher average (STL SP in red).

Starting Pitcher Stats:  Through May 19, 2019

K%	BB%	HR/FB	ERA	FIP	xFIP
25.8 Flaherty	4.3 Mikolas	14.5 NL SP	4.13 NL SP	4.17 NL SP	3.88 Flaherty
22.7 NL SP	8.1 NL SP	17.5 Wainwright	4.19 Flaherty	4.29 Flaherty	4.16 NL SP
20.3 Wacha	8.9 Flaherty	17.6 Flaherty	4.40 Hudson	4.76 Wainwright	4.34 Mikolas
19.9 STL SP	9.1 STL SP	18.5 Mikolas	4.58 STL SP	4.87 Mikolas	4.35 STL SP
19.2 Wainwright	9.4 Wainwright	19.0 Wacha	4.75 Wainwright	4.95 STL SP	4.42 Hudson
16.3 Hudson	10.1 Hudson	19.5 STL SP	4.88 Mikolas	Hudson 5.52	4.42 Wainwright
16.0 Mikolas	13.5 Wacha	25.7 Hudson	4.93 Wacha	5.57 Wacha	4.96 Wacha

Just how bad has it been? Quite bad. But it’s the contours that are most interesting. Some observations:

1.  The home-run bug has bitten the Cardinals very badly. Every single starter has a higher than average HR/FB.

2.  The Cards are issuing way too many free passes. Dakota Hudson and Michael Wacha are the obvious culprits. Wacha, in particular, has been horrendous. But the Adam Wainwright BB% cuts against a Wainossance narrative, because it is far higher than what the veteran was posting in his prime.

3.  The Cardinals don’t strike anyone out in this era of strikeouts. Only Flaherty is above average in this regard. And Wainwright, Hudson, and Mikolas are not even close to average.

4.  The Cardinals starters’ combination of low strikeout rate, high walk rate, and high HR/FB rate means that they have actually been fortunate with respect to their runs allowed. This is reflected in the comparison between their collective 4.95 Fielding Independent Pitching (FIP) and 4.58 Earned Run Average (ERA).

5.  It’s fair to expect their HR/FB to regress. xFIP substitutes the league-average HR rate for the pitchers’ actual HR rate in order to bake regression to the mean into FIP. Doing this gives the Cards an xFIP of 4.35 that is far more respectable. Of course, with their low K rate and high BB rate, their xFIP is still below average.

6.  A lot of fans zeroed in on Hudson early on and deservedly so. But this table shows that there is more than enough blame to go around, especially when it comes to the veterans. Wacha, in particular, has been terrible.

7.  While the Wainossance narrative has been overblown, the Wagonmaker is a perfectly find No. 5 starter. The problem for the Cardinals is having Waino, Wacha, and Hudson in the same rotation. They essentially have had a No. 5 in Wainwright and two replacement-level starters after him in Wacha and Hudson.