St. Louis Cardinals vs. Milwaukee Brewers: Can the bullpens keep it up?

Entering the clubs’ third series before May Day, the Milwaukee Brewers and St. Louis Cardinals find themselves tied for second in the National League Central race. The Pittsburgh Pirates sit atop the division standings, with a one-game lead over both the Redbirds and Brew Crew. St. Louis and Milwaukee are well positioned in the early-season standings despite bad starting pitching.

In fact, calling the performance of the two teams’ starters this young season “bad” might be a bit charitable. Their rotations have posted numbers among the worst in all of MLB. Among the 15 National League clubs, they rank at or near the bottom of the rankings in old-fashioned and advanced stats alike.

The following table contains stats through April 21, 2019, and how they rank in MLB and the NL.

Starters:  Cardinals vs. Brewers

Team	ERA	MLB	NL	FIP	MLB	NL	xFIP	MLB	NL
STL	5.06	22	13	5.62	28	15	4.55	21	14
MIL	5.62	25	14	5.49	27	14	4.54	22	15

That is an ugly collection of top-line stats, whether you prefer Earned Run Average (ERA) or Fielding Independent Pitching (FIP), which is factored using innings pitched, strikeouts, walks, and homers allowed. Even when one adjusts for expected home-run rate via xFIP, it’s not pretty for the Redbirds or Brew Crew. Collectively, the starters for both teams have not done much well.

For years (maybe even a decade), I have been pining for a stat to measure strikeout and walk rates to league average, while adjusting for home park. Fangraphs has delivered. It’s a wonderful stat to get an idea of how teams compare.

If you’re familiar with other “plus” stats, you’ll know how these work. They adjust for park effects and league, with 100 being average. From the hitter’s perspective, each point above 100 is one percentage point better than average; each point below 100 is one percentage point below average.

For this exercise, I’m going to use K% and BB%. While writing at Viva El Birdos, I explained why I prefer these two stats to K/9 and BB/9 when looking at pitcher performance. I’m also going to add K/BB because it shows the interplay between the strikeouts and walks by the starters. Additionally, I’ve included HR/9 and HR/9+ because HR/9 is the stat to which Fangraphs gave the “plus” treatment.

The following table contains stats through play on April 21, 2019.

Starters’ Peripherals:  Cardinals vs. Brewers

Team	K%	K%+	BB%	BB%+	K-BB%	K-BB%+	HR/9	HR/9+
STL	20.6	86	9.4	103	11.1	84	2.06	154
MIL	23.7	99	9.7	105	9.9	94	2.14	161

The Cardinals are not striking out many batters. The Brewers are okay at it. Both are doing a decent enough job when it comes to walks. Their low strikeout numbers, even when combined with their decent walk rates, combine to drag down their K-BB% when compared to MLB overall.

Now let’s get to the main issue:  Home runs. Weirdly, it appears that HR/9 is calculated from the batter’s perspective. The Cardinals rank last in the NL in HR/9; the Brewers second-to-last. So their high HR/9+ is not good. It’s very bad.

How has this impacted the teams early? It’s put a burden on their bullpens. The following table contains stats through play on April 21, 2019.

Starter and Reliever IP:  Cardinals vs. Brewers

Team	SP IP	MLB	NL	IP/GS	MLB	NL
STL	105	23	14	5.00	23	13
MIL	113.2	15	9	4.94	24	14

This might be a bit of October philosophy bleeding into the regular season. The approach that Tony La Russa pioneered in the 2011 postseason was used by many a postseason participant in recent years. But the sprint of October is not the marathon of the 162-game regular season. Bullpenning like it’s fall in the dog days of summer might make it difficult for a team to secure a postseason berth.

Conventional wisdom has long held that starter innings are the foundation for bullpen success. Requiring fewer innings from relievers allows the manager to more effectively deploy relievers by proactively playing matchups rather than reactively trying to cover innings. What is the sweet spot between the three-times-through-the-order penalty and the need to have fresh arms with which to play matchups? It appears that the 2019 Cardinals and Brewers might very well be on a trajectory to find out.