Red Sox: Did Eduardo Rodriguez avoid his changeup last night?

The changeup is one of Red Sox starter Eduardo Rodriguez‘s best pitches. So why did he stay away from it in Friday’s blowout loss to the Yankees?

The changeup has been good to Eduardo Rodriguez. Very good. In fact, it’s one of his best pitches. Last season he saw hitters manage just a .254 wOBA and a .265 xwOBA (expected). This season the wOBA against is .311 and the expected version is .274. It has been his highest wiff percentage pitch in both of the last two seasons at 38.6 and 35.3% respectively. These figures are taken from his Baseball Savant player page, for those curious. What do they mean?

wOBA is weighted on base average. It’s a composite offensive statistic, similar to OPS. But it gives different weights to various outcomes instead of assuming all times on base are equal. Generally speaking, it is considered a more accurate gauge of offensive production than OBP or OPS. An average wOBA is about .320 so the figures above all represent better than average results for Eduardo Rodriguez when he throws the pitch. When does he throw it normally?

His usage has been pretty consistent throughout his career.

For location, Eduardo Rodriguez throws the changeup almost exclusively in the same quadrant of the plate. Down and in against lefties, and down and way against right handed hitters. If you are behind the plate (the catcher’s view), that’s the lower right hand corner. He throws it far more often against right handed batters. That means he’s using it as a chase pitch to try and generate swings and misses. As the wiff rate referenced above suggests, it works. When thrown to lefties, the goal is to bust them down and in and induce weak contact or more wiffs.

It’s not really a put-away pitch, though. His sinker and cutter usage both come up with two strikes while the changeup usage stays similar. You might find that odd, considering the swing and miss success he has with it. But it appears that he uses the changeup, like his fastball, across all situations fairly similarly. This is probably because he feels confident in his ability to control the pitch and can use it in concert with the fast ball to move toward getting ahead in the count. Or toward pulling even when he falls behind. His cutter, sinker and slider all have their usage percentages drop when he is behind. So it’s a go-to pitch even if his overall percentages show the cutter being used more often overall.

What was the deal last night?

According to Brooks Baseball, he ended up throwing 18 changeups out of 95 total. That’s not out of line with his 18.1% usage on the year. Sounds like it was a typical night, right? Well, not so fast. This tweet from Red Sox Stats suggests he was avoiding it early on.

Alex Speier followed with this later in the game:

That’s where the 18 changeups listed by Brooks Baseball comes in. The pitch categorizations are often updated in the hours after a game is finished. Pitch classifications are basically guesses inferred from velocity, spin, and movement. If Eduardo Rodriguez didn’t have a great feel for the changeup last night, it may have gotten misclassified. When we look at the breakdown by inning, we can see at least eight thrown in the first four innings. Seven of those were thrown close to 90 MPH or higher.

When we add in the rest of his start, we see at least seven of them down closer to the 88 MPH mark. It looks very much like he wasn’t getting the full separation he is used to on his changeup early in the game.

Does one MPH make that much of a difference?

Well, the Yankees did five runs of damage in those first four innings. If the changeup wasn’t separated enough from his fastball, it may not have been succeeding in putting Yankees hitters off balance. Since his cutter was living in that same 90-92 MPH range that the change was being thrown in early on, it may have reduced the effectiveness of both pitches. Pitching is all about deceiving the batter. If they are expecting a fastball, and you can get a good change or a soft breaking pitch across the plate, they have to adjust mid-swing. When several of your pitches are coming in at around the same velocity, that adjustment isn’t as difficult.

So, yes. That one MPH can actually be a significant difference. And it explains why during the game it appeared as though he wasn’t throwing any changeups. He was, in fact, throwing them. He just didn’t have a good feel for the pitch so it wasn’t behaving like it usually does.

It’s likely not a long term issue.

That’s not really that big a deal in the grand scheme of things. Pitchers lose the feel for a pitch on an individual night all the time. That’s part of why they throw a bullpen earlier in the evening. They need to see what’s working and what’s not. In the post game, Alex Cora confirmed this line of thinking when he said:

"“Stuff was there, it was kind of like a weird game, honestly,” said Cora. “I don’t know if there was enough separation also with the fastball and changeup. I can’t recall too many swings-and-misses with the changeup or bad swings on the changeup, and we know that that’s his pitch. I’ve got to take a look at it tomorrow.”"

Next: Red Sox and Yankees square off for the division lead.

What do you think of Eduardo Rodriguez’s performance last night? Any other factors worth considering? Let us know in the comments!