Michael Wacha as a Reliever as a Starter

If the Cardinals are to earn a berth in the World Series Friday night, they’ll have to do so opposing a team starting Clayton Kershaw, presumably baseball’s best starter. Taking the mound for the Cardinals will be a still-mostly-unproven rookie in Michael Wacha, and on the face of it, that puts the Cardinals at a considerable disadvantage. But, a few things are working in their favor. One, the Cardinals are at home, and the home-field advantage is undeniable, even if it’s almost impossible to observe in the moment. Two, Wacha and the Cardinals just beat Kershaw and the Dodgers earlier in this very series, by a 1-0 final. So nothing here is impossible. And three, some people figure that by this point in the season, pitchers are pitching on fumes. Wacha, however, only seems to be getting stronger. The gap between Kershaw and Wacha exists and is big, but right now it’s probably not as big as you might’ve thought.

There’s something to be said for postseason adrenaline. There’s something to be said for Wacha still finding his way as a starter in the bigs. And there’s something to be said for the way Wacha has been handled this year, as the Cardinals didn’t want a repeat of the Strasburg Shutdown in 2012. The Cardinals anticipated the future, they wanted to have Wacha available down the stretch, so they gave him some breathers over the course of the summer. As a result, Wacha’s stabilizing a late-season rotation that’s missing Shelby Miller. He’s not just throwing his pitches — he’s throwing his pitches better.

Wacha’s first four major-league appearances were as a starter. After that, he shifted to the bullpen for a few weeks, then he returned to the rotation, making five starts in September and with this being his third start in October. So we have information for Wacha occupying two roles, and we have information on season progression. The last three times Wacha has taken the mound in particular, he’s been dominant, and some of the data underneath reveals an interesting pattern. The following information came from Brooks Baseball, and I trust them to get this stuff right. Wacha is by no means wearing down. Wacha’s doing pretty much the exact opposite.

Here are Wacha’s average pitch velocities as a reliever:

Fastball: 95.5 miles per hour
Changeup: 86.8
Curveball: 76.7

For whatever it’s worth, he threw hardly any curves out of the bullpen, but there you go. Now, here are Wacha’s average pitch velocities over his first eight big-league starts:

Fastball: 93.6 miles per hour
Changeup: 85.9
Curveball: 75.6

There’s nothing in there you wouldn’t expect. We’ve long understood that guys throw harder out of the bullpen than when starting, because as a reliever you don’t have to know how to pace yourself. Starters have a certain amount of energy they distribute over 100 pitches or so. Relievers have a certain amount of energy they distribute over 10 or 15 or 20. It’s normal to lose one or two ticks in a longer stint, and this goes a long way toward explaining why relievers also post better numbers.

Finally, here are Wacha’s average pitch velocities from his last three starts, beginning September 24:

Fastball: 95.5 miles per hour
Changeup: 88.4
Curveball: 77.3

In the first of those three starts, Wacha carried a no-hitter until there were two out in the ninth. In the second, he carried a no-hitter until there was one out in the eighth. In the third, he shut out the Dodgers for nearly seven innings. Wacha’s pitching the best he has all year, and driving that, at least in large part, is that he’s throwing as a starter as if he’s a reliever. His fastball velocity is where it was out of the bullpen. His secondary pitches are even faster. Wacha’s beyond 160 innings on the year — there was talk the Cardinals didn’t want him to get past 150 — but here there aren’t any signs that he’s wearing down. Very much the opposite of that, either because Wacha is pumped up, or he’s learned some things over the summer, or both or more than that. Again, someone else might have a good explanation. I just have the data, and it’s the data that helps us project performance.

It’s probably also worth noting that Wacha threw 13 curves the last time out, and 14 curves the time before that. In no other appearance had he thrown more than nine, so he could be developing increased confidence in his breaking ball. But then, in that start September 24, the curve got thrown just three times, so if that’s a factor, it’s a secondary one. The Dodgers, Friday night, should be aware of Wacha’s curve, but more importantly they should be prepared for a hard thrower. A guy who’s throwing harder is going to perform better, and so Wacha right now seems to be a step above how people thought of him even last month. He’s closer to Kershaw, if you will, even if he’s still not that close. Every bit matters.

The Cardinals wanted to avoid a Strasburg situation, so they planned ahead to have Wacha available late, and now they’re getting all the benefits. In that sense, this is just another example of the Cardinals getting something right, where another organization might’ve gone wrong. I am open to the argument that there’s a downside to this. Wacha’s past his soft innings limit, and he’s throwing as hard as he has all season. Maybe that’ll be bad for him in the long-term — maybe his arm is in a weakened state, and this is increasing his injury risk. I have no idea and I don’t care to speculate, but it’s not altogether unreasonable. There’s a lot we don’t know and Wacha’s putting a lot of strain on his body.

But what the Cardinals care about right now is winning, and ideally winning this Friday night so they can advance to another World Series. They’ll be up against it, having to face baseball’s best starter, but they’ll be going with a pretty good starter of their own, a starter who looks as strong as he ever has. Michael Wacha, ever so briefly, was a dominant reliever. These days he looks like a dominant starter throwing like a reliever. Let it not be advanced that Game 6 is a mismatch.