Michael Wacha Has Been Bad for Longer Than You Think

The Milwaukee Brewers have pummeled the St. Louis Cardinals this week. The starters, in particular, took ition the chin. First, rookie Dakota Hudson was knocked out early and then Jack Flaherty. Now the Cardinals turn to veteran Michael Wacha as they hope to avoid a sweep.

If you read stltoday.com, you might have thought that Wacha was a cornerstone of the Cardinals rotation entering the season and deserving of a contract extension from the club. In 2018, Wacha posted the following traditional stat line:

• 15 GS
• 8 pitching "wins"
• 2 pitching "losses"
• 3.20 ERA

If Wacha had been healthy, he may very well have made the National League All-Star Game. But that’s more of an indictment of the All-Star Game selection process than an endorsement of the quality of Wacha’s pitching. Thinking that the above line is that of a good pitcher who is deserving of a contract extension is the type of mindset that leads one to trade Jim Edmonds for Ken Bottenfield (and Adam Kennedy — but still, Jimmy Ballgame!).

Pitchers have a limited amount of control over what happens when they pitch. Their fielders can have a significant impact, for better or worse, on how many runs the other team is able to plate. The official scorekeeper can help or hurt a pitcher’s ERA with a ruling on any given day. And sometimes the ball finds or avoids fielders, regardless of how well its hit. Such is the beauty of baseball. Like life, its randomness can be a blessing or a curse.

Thus, when assessing a pitcher’s performance, it’s best to focus on the outcomes that the pitcher most directly impacts. I write “most directly” because there is no metric that creates a crystal clear signal perfectly reflecting a pitcher’s individual performance and underlying skill. There is still noise.

For example, the catcher’s pitch-framing can have a significant impact on called balls and strikes — and by extension, strikeouts and walks. This especially true when the catcher is one Yadier Benjamin Molina, future first-ballot Hall-of-Famer. (You should read David Appelman on the subject.)

All of this is to say that focusing on strikeouts, walks, and type of contact is not perfect. It’s simply to say that such an approach better reflects individual pitcher performance than ERA and pitching “wins.” So that is what we will start with in our look at Wacha.

For a backdrop, let’s compare Wacha’s 2017 and 2018 seasons. If I were looking at the back of a baseball card, I might see that Wacha went 12-9 in 2017 and 8-2 in 2018. And that he 4.13 ERA in 2017 compared to a 3.20 ERA the following season. Such a limited approach suggests that Wacha improved his performance from two seasons ago to last.

A deeper dive reveals that Wacha’s pitching performance fell off from 2017 to 2018 (and has not rebounded in this young 2019 season).

Wacha:  2017 vs. 2018

Year	IP	K%	BB%	LOB%	BABIP	ERA	FIP	xFIP
2017	165.2	22.5	7.9	71.5	.327	4.13	3.63	3.88
2018	84.1	20.0	10.1	75	.249	3.20	4.22	4.12
Diff	-81.1	-2.5	+2.2	+3.5	-.078	-0.93	+0.59	+0.24

If you were drawing up a method by which a pitcher could lower his ERA, it would not include increasing his walk rate (BB%) by 2.2 points (a 27.84 percentage increase) or r decreasing his strikeout rate (K%) by 2.5 points (an 11.11 percentage decrease).

And if you were devising a sustainable way for a pitcher to lower his ERA, it would not be based on reducing his Batting Average on Balls In Play (BABIP) by 78 points. Especially with the changes in quality of contact, as measured by the Fangraphs Batted Ball data:

Batted Balls vs. Wacha: 2017 vs. 2018

Year	Soft%	Medium%	Hard%	GB%	LD%	FB%	IFFB%
2017	20.2	51.8	28	48	21.1	30.9	8.2
2018	15.9	41.5	42.7	43.2	29.5	27.4	7.6
Diff	-4.3	-10.3	+14.7	-4.8	+8.4	-3.5	-0.6

Reducing BABIP is typically not achieved by:

• Decreasing soft contact;

• Decreasing medium contact;

• Increasing hard contact substantially;

• Decreasing grounders; and

• Increasing line drives.

Statcast data at Baseball Savant is in line with the Fangraphs batted ball data. Statcast tracks Wacha’s average exit velocity at 86.3 mph in 2017 compared to 87.8 mph in 2018. The percentage of barrels by opposing batsmen increased from 5.6% in 2017 to 7.7% in 2018. This adds up to a corresponding uptick in Expected Weighted On Base Average (xwOBA) against Wacha from .350 in 2017 (bad) to .370 in 2018 (worse). For some context, the MLB non-pitchers posted a .320 wOBA in 2018.

This is all bad, some of it alarmingly so. Yet somehow Wacha’s ERA shrank by 93 points, defying the gravity of his peripherals. Fielding Independent Pitching (FIP) takes batted balls that are fielded out of the equation and focuses on Ks, BBs, and HRs. Wacha's FIP went from 3.63 in 2017 to 4.22 in 2018. Adjusting for park effects, he went from better than average (85 FIP-) to worse than average (105 FIP-).

Perhaps most concerning is the fact that 2019 hasn't given us much on which to base hope for improvement (but that's a post for later, when the sample size is larger).

The St. Louis front office has long relied on advanced metrics when gauging pitcher performance and executing contracts, so it should come as no surprise that the team did not engage Wacha in extension talks. The veteran has not pitched well in a good long while when we consider more than ERA and pitching "wins" and "losses." Right now, the Cardinals are likely thinking more about removing Wacha from the rotation than giving him a contract extension, and understandably so.