Three straight good starts for Michael Wacha have Cardinals fans wondering if they should expect more.

Last year, Michael Wacha finished a wildly disappointing season on the disabled list. After showing the potential to be a number 2 or 3 starter for years to come in 2015, Wacha posted a 5.09 ERA with an FIP near 4. No matter how you looked at his numbers, Wacha was just a poor pitcher in 2016. Coming into camp, Cardinals management started talking him up a bit, but it was hard to believe the hype. Three starts into the season, Wacha is providing the hope on his own.

Across 18.2 innings, Wacha owns a 2.41 ERA and 1.13 WHIP this year. While many expected him to lose the fifth starter spot out of camp (myself included), Wacha is positioning himself to stick in the starting rotation all season long. However, in just three starts, the usual sample size caveats apply. We need to look at a lot more than just ERA and WHIP to know if this new Wacha is for real.

The Peripherals

Unfortunately for the Cardinals, the peripheral stats don’t paint as kind a picture of Wacha. The strikeout and walk rates are fine. In fact, his strikeout rate is up a tick from where it usually is, and his walk rate has always been very good. Wacha’s problem is the home runs. When it comes to home runs, there is some debate over how much the pitcher is at fault. Wacha is giving up 1.45 HR/9 this year, which sounds unsustainably high on the surface. A quick look at his groundball rate will tell you otherwise.

Wacha’s groundball rate is a career low 34 percent. While he is giving up a lot of homers, his HR/FB rate is not that far off from what it should be. Instead, Wacha just can’t seem to induce any grounders. Wacha’s FIP and xFIP currently sit at 3.99 and 3.85, which are not far off from his marks the past two seasons. FIP tends to be a better predictor of ERA than ERA itself, which could indicate trouble is lurking for Wacha.

On the other hand, we don’t know that the groundball rate is sustainable. Groundball rate usually doesn’t change much for pitchers over the course of a career. Perhaps it is more likely that Wacha will regress to the mean in that area. That would entail an improvement in groundball rate, and thus fewer home runs. Ultimately, Wacha’s peripheral stats aren’t great, but there is a road for correction there.

The LOB conundrum

Pitchers don’t choose when they give up their hits. In other words, a pitcher who gives up three hits in a row, then retires the next ten batters is just as effective as the pitcher who retires ten of thirteen batters with the three hits coming in different innings. By extension, a pitcher’s left on base percentage may fluctuate, but it should be predicted by a function of the baserunners that the pitcher gives up.

So far, Wacha has stranded 89.3 percent of baserunners. Wacha’s 1.13 WHIP is good, but not that good. For reference, Clayton Kershaw’s career strand rate is below 80 percent. I would be understating it if I said that Wacha has gotten lucky stranding runners thus far. His career strand rate is a hair under 73 percent, and there is no reason to expect that to change much. If Wacha continues to give up fewer baserunners, perhaps those that do get on may get stranded more often. But until we see that trend continue, we can’t assume that will happen.

None of what I just said will affect the peripheral stats. The inflated strand rate has kept Wacha’s ERA down, but it did nothing to his ERA indicators. FIP and SIERA do not take strand rate into account, so we shouldn’t expect worse than what those numbers say. Instead, view this as a note that Wacha will not continue with his current ERA of 2.41. That doesn’t mean he can’t be good; it just means he isn’t this good.

Repertoire Adjustments

Before just siding with the stats, I tried to check and see if there were any signs of a different Wacha this year. Wacha’s velocity is on par with where it was in past Aprils, but he might have tweaked his curveball. The following graphs from Brooks Baseball show the month-by-month horizontal (left) and vertical (right) movement on his pitches.


While most of his pitches show no change from past year to this one, his curveball does. His curveball seems to be breaking more both to the left-hand side and downward. I should note that this may be nothing. We could just be capturing some random three-game variance here. But Brooks Baseball provides confidence intervals on those breaks, so I am inclined to think that Wacha might have changed something this offseason.

Generally, more movement is better, but this might not be a big change. The peripheral stats don’t show a huge change, so maybe this really isn’t worth much. Nevertheless, it is important to note the differences that we have seen so far.

Speaking of differences, Wacha debuted a new sinker earlier this month. Joe Schwarz at Viva El Birdos noted Wacha’s new pitch earlier this year, and it’s definitely something new. He hasn’t thrown it enough yet for me to give a real analysis, but it’s something to keep an eye on. Again, the key is that we are seeing a slightly different Wacha. Wacha may not improve much, but he made some changes after an abysmal season.

What does it all mean?

Well, we can throw the 2.41 ERA out the window. That number is not indicative of how Wacha has really pitched or will pitch in the future. ERA indicators such as FIP are a bit more accurate, but I think they overshoot it a little bit. Wacha has pitched like someone who should give up about four runs per nine innings so far. However, I think his groundball rate will improve to his career norm, and then we will see a drop in his FIP.

None of that takes into account the repertoire adjustments that Wacha made, either. If Wacha’s curveball really is different and better, then he could be even better. If Wacha’s sinker becomes an effective pitch, then he could be even better. For now, I would set his current FIP of 3.99 as a baseline, with the expectation that he will beat it. By how much is tough to say. I doubt he does much better than a half run better. I don’t think the sinker and curveball will mean enough to do any better. Factoring in the potential for strikeout regression, I think 3.75 is a good target for Wacha to shoot for.

Perhaps 3.75 sounds disappointing given Wacha’s start, but it shouldn’t be. If you threw out that number before Opening Day, then the Cardinals would have taken it without hesitation. We only have slightly more information now, and I still think that’s a good deal for the Red Birds. They got a fifth starter back after injury, and he can hold his own at that pace. We should definitely keep an eye on his new pitches and the groundball trend, but the first few outings for Wacha have given us a glimpse of what his season might be like.

Photo Credit: Adam Hunger – USA TODAY Sports