Zack Greinke Isn’t Out of the Woods

Since people take us for experts for some reason, we’re commonly asked what we consider important in the season’s very early going. What’s most important — and this should be abundantly clear — is that there’s active baseball in the first place. At the very least, there’s spring-training baseball, and as of just yesterday, there’s meaningful baseball. That’s it! That’s the whole point. Everything else is a detail.

But since we all get worked up over the details, we’re asked which details are most important early on. Statistically, the answer is, not much. A high or low batting average isn’t too suggestive. A high or low ERA isn’t too suggestive. A win or loss here or there are but ones of dozens. The more important things are the measurements that take less time than others to stabilize. Changes in, say, power. Changes in contact. Or changes in velocity. There are few things that stabilize in less time than how fast a pitcher throws. This is why so many of our March and April stories and tweets are about unusually fast or slow fastballs. This all brings us to Zack Greinke, the Diamondbacks’ opening-day starter.

The most important thing that happened for Arizona is that they won. They won against a superior opponent on Sunday, and they won against a superior pitcher. They won even though that superior pitcher blasted a pair of home runs. Every win counts the same, no matter when it happens, so if the Diamondbacks intend to stick in the race, days like yesterday help. They didn’t win because of Zack Greinke. They also didn’t almost not win because of Zack Greinke. He started and he was fine, and then other innings happened.

Greinke has been in the spotlight. I mean, he’s been in the spotlight because he signed a gigantic contract, and not even that long ago he resembled an ace. He is one of Arizona’s more visible players. But he’s been in a more recent spotlight because he wasn’t throwing as hard as he usually does. This spring, his velocity was down, and that always gets the attention of the nerds. Greinke’s got a lot to live up to. He’s also 33 years old. He’s critical with regard to any organizational plan to stage a playoff push. Like it or not, it can’t be avoided — eyes are on Greinke’s heater. As Greinke goes, perhaps, the Diamondbacks go.

Maybe, then, the first start was modestly encouraging. Greinke topped out around 93 miles per hour, and his fastball averaged 90.8. That would be down a half-tick from last year’s average, but it was also the first start of the season, and arms haven’t yet been built up to 100%. Velocity tends to increase as the season wears on. So, maybe, Greinke’s just fine! At least as the fastball goes, he could be back to normal.

However, I’m unconvinced he’s entirely out of the woods. And I’m unconvinced because of the bigger context. In Sunday’s game between the Giants and the D-Backs, 11 different pitchers were used. Here’s a table of all their average 2016 fastball velocities, and their Sunday averages:

Average Fastball Speeds
Pitcher 2016 2017 Change
Jorge de la Rosa 91.0 94.0 3.0
Mark Melancon 91.8 93.7 1.9
Madison Bumgarner 90.9 92.7 1.8
Ty Blach 91.4 92.8 1.4
Hunter Strickland 96.8 98.0 1.2
Tom Wilhelmsen 94.8 96.0 1.2
Fernando Rodney 94.4 95.2 0.8
Derek Law 92.9 93.6 0.7
Andrew Chafin 92.8 93.1 0.3
J.J. Hoover 91.6 91.8 0.2
Zack Greinke 91.3 90.8 -0.5

You’d think, so early, you’d see more lines like Greinke’s. More small dips, given that yesterday was April 2. Yet, out of the 11 pitchers, Greinke was the only guy to average a lower fastball speed. The average here is a 1.1 mph increase. The median is +1.2. For the visual learners, here’s the same information, shown in a more colorful way:


Say, that Jorge de la Rosa bar is encouraging, but then he’s also trying to be a full-time reliever now. Last year, he was a starter, and even though he made three relief appearances, and even though those are my point of comparison here, he didn’t know what it was to be a reliever in 2016. You’d expect a big de la Rosa boost. The Greinke bar is troubling. There are but two ways to take this:

  1. Everyone but Greinke throws harder now
  2. The reported velocities are a little hot, and Greinke’s “true” velocity was down even more

Of the two, the second feels far more likely. Which would mean we’re not talking about being down 0.5 mph. We’d be talking about being down, say, 1.5 or 2.0 mph. That’s worse. You can see how that’s worse.

Let’s speak in specific generalities. Since 2006, there have been 969 cases of pitchers who’ve thrown 100 or more innings in consecutive years. On average, in the second year, fastball velocity has dropped by 0.2 mph, and ERA- has increased by three points. FIP- has increased by two points. That’s basic regression to the mean. Regulars tend to get very slightly worse, because to become a regular implies a certain amount of overachieving.

Out of that pool, there have been 159 cases where a pitcher lost at least 1 mph. And remember, these are cases where the pitcher still got to at least 100 innings, so this is selective for more successful individuals. This group has averaged a velocity loss of 1.4 mph, and an ERA- increase of 13 points. It’s averaged an FIP- increase of 10 points. The ERA- change is worse than the overall pitcher sample by 10 points. The FIP- change is worse by eight points. There’s more that goes into pitching than velocity. Velocity, though, is still greatly important.

The caveats here are significant. For one thing, we still don’t know where Greinke is going to end up, in terms of his arm strength. He could continue to build, and he could end up back to where he was. It’s conceivable he could even end up throwing harder. No reminder necessary — we’re one game in. And then there’s the matter of Greinke being a command pitcher, more than a power pitcher. Look at what Kyle Hendricks just managed to do with vastly inferior stuff, at least in scouting terms. If Greinke stays around the edges and loves his time working with Jeff Mathis, he could survive on weak contact. Marco Estrada just lost 1.2 mph, and last year he lowered his FIP- by 12 points. Masahiro Tanaka just lost 1.2 mph, and last year he lowered his FIP- by 15 points. Greinke still knows how to be a good pitcher, and it’s not like his stuff has completely abandoned him.

It’s just, as always, pay attention to this as the days turn into weeks. Early on, we have to guess about everything, and our guesses are only partially educated. Time reveals reality, and we don’t know what Zack Greinke’s 2017 reality will turn out to be. The earliest possible indicator, though, is less than positive. Greinke might’ve lost some more of his margin of error. And if that can be said of him, it can also be said of the team that he plays for.

Jeff made Lookout Landing a thing, but he does not still write there about the Mariners. He does write here, sometimes about the Mariners, but usually not.

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5 years ago

Flemming did mention on the ESPN broadcast that mlb was using a new algorithm to calculate velocity, so I’d put strong money on theory 2.

Max Power
5 years ago
Reply to  br1112

I think to get the exact averages Jeff is using a different datasource than watching the broadcast and recording fastball velocities, but I did initially think the same thing. Important thing to remember for viewers.