Not much has gone right for Chad Green early this season. After emerging as one of the team’s essential bullpen arms over the last two years, a few bad outings have pushed Green down in the pecking order. Unfortunately, it only got worse on Sunday. Up 5-0 against Kansas City, Green was handed a low leverage opportunity to help himself right the ship. After three hitters and no outs recorded, enough was enough. Adam Ottavino eventually allowed those inherited runners to score, but the performance ballooned Green’s ERA to 12.27 in just over seven innings of work.

Green’s problems generally boil down to hard contact and a lack of whiffs, as Bobby wrote about recently. Interestingly, as Bobby noted, hitters have historically been able to clobber Green’s trademark fastball, but only when they actually are able to make contact. As last season wore on, hitters gradually became more successful at putting bat on ball against the pitch, and this season that phenomenon has hit Green like a freight train.

Logically, it makes sense that major league hitters will eventually figure a pitcher out with enough looks, but this still seems weird to me. It’s not like the league suddenly figured out Green threw a ton of fastballs late last season. He’s been doing it for a couple of years now. Perhaps the pitch is simply more hittable now.

A few things that make any given pitch hittable are velocity, spin rate, movement, and location. Let’s see what’s going on with Green’s fastball. It’s his bread and butter, after all, and what made him successful in the first place.

Yikes. His fastball velocity has fallen significantly since last May. Maybe he’s still building up velocity, like many hurlers do early in the year, but that’s still an alarming trend.

Green’s fastball spin rate has dropped, albeit slightly, since 2017. It’s at 2434 RPM this season, down 10 RPM from 2018 and 50 from 2017. Probably within the margin of error, so I don’t think there’s much to make of this. He’s still comfortably above league average in that department. Movement-wise, Green’s fastball has always been pretty straight. Yet, because of his spin, it’s deceptive and has a rising quality (even though that’s physically impossible). Simply put, it just doesn’t drop as much thanks to backspin. And unsurprisingly, his movement on the pitch hasn’t altered. All good news here, at least.

What about location? Green’s never been a command guy, and hasn’t needed to be.

As you can see, Green pours fastballs over the heart of the plate, and that hasn’t changed early this season.

So really, the only thing that has changed is Green’s fastball velocity. Is that really enough to result in this?

I don’t know. I mean, surely a slightly slower fastball makes for a little more contact. But, it’s not like Green has gone from a mid-90s heater to high-80s. It’s still humming in there at 95 miles per hour with great spin to boot.

Maybe it really is just a matter of hitters growing accustomed to Green’s patented offering. It took some time, but perhaps opponents have finally adjusted to Green’s approach. It’s never been a secret that Green was going to attack hitters with the fastball, but even knowing that didn’t hinder his success. That’s a testament to how effective the pitch has been for him historically, as it took a long time for hitters to finally start improving against it.

If Green can make something of his slider or re-introduced splitter, perhaps his fastball can return to its former glory. He’s certainly trying to incorporate those pitches, as his fastball usage has decreased this year (albeit still at a very high 72 percent clip). Still, they aren’t even average options at this time, which ostensibly makes it easier to key in on the fastball.

Last but not least, it’s still really early in the year. Green’s not going to run a 30 percent home run to fly ball rate, .375 BABIP, and 50.9 percent strand rate all season. He’d have to be truly broken to do that. Some regression to the mean must be coming, even if he remains a one-pitch pitcher.

For the time being, it makes sense for Aaron Boone to deploy Green in low leverage situations like Sunday. It’s incredibly frustrating that he couldn’t get the job done then, but those are also the only spots he really deserves at this point. Let him earn his way back into important situations. His fastball is still good enough to get hitters out, but perhaps he needs to work out the kinks in low stress situations. Whether that’s refining command by aiming for the corners a bit more or getting a better feel for his secondary stuff, Green will have to counter the rest of the league’s adjustment to his fastball. Hopefully that’s sooner rather than later, because this bullpen needs help.

The beginning of the season has been a struggle for the Yankees, who have won only 5 of their first 13 games. A large part of those struggle is that the players currently on the IL would likely win the AL Central if healthy and surrounded by replacement level players—turns out it’s tough to win games when 5 regulars, your ace starter and ace reliever are simultaneously out. The Yankee bullpen has yet to pick up the slack, with both Chad Green and Zack Britton not performing to expectations.

There is still quite a bit of noise in the data at this point in the season—seriously, it’s been only 13 games even if it feels like it’s been a lifetime—and early-season small sample size has a way of making one look like a fool by the time the weather warms up. But we can still discern trends and identify areas to watch as the season grows older, and that does have real analytic value. Regarding the Yanks bullpen, I am considerably more concerned with Green’s struggles than Britton’s over the long-run, so let’s take a look at what could be going wrong for the Yankees once-fireman.

Fastball Reliance

We’ve covered this quite a bit at RAB before, so you should all be familiar by now: Green really, really relies on his fastball. Check this out:

Since Green fully became a reliever, and a good one in that, in 2017, he has essentially used only two pitches: his four-seam fastball and his slider. The slider is more for show, as it’s not that effective. That’s why he ends up using the four-seamer more than 75% of the time. Last year it was even higher than that, peaking at 93% of the time last June. That’s because his slider isn’t all that effective. He’s hovering at about 75% fastballs so far in 2019, though it’s worth noting he’s re-added his splitter to his arsenal, which Mike covered a few weeks ago. It’s too early to worry about how effective it is—but it’s interesting that Green is trying the splitter again.

Green really needs his fastball to be effective for him to be successful, and while he was still very good last year, there are clear signs that his hitters were adjusting to his fastball. Take a look at this table, comparing his fastball in 2017 and 2018:

Those are still good numbers, sitting comfortably above-average to elite, but that doesn’t mean that there aren’t red flags here, especially for a fastball only pitcher. Hitters started squaring Green up a lot more in 2018, as evidenced above and by an increased HR/9 and reduced K%. It was a lot harder for Green to blow fastballs by MLB hitters in 2018, and that has been so far again this year. That’s probably why he’s trying to fold in more splitters: by introducing that pitch, he hopes to keep hitters off balance and regain that four-seamer’s elite effectiveness.

Existing Red Flags

Relievers are notoriously fickle and unpredictable—that’s why those who are predictable usually tend to be well-paid—and one pitch guys like Green are more susceptible to quick, ugly backslides. (Remember the relievers are fungible days? That was all the rage in the analytic community a few years back.) In fact, there have already been a few existing red flags, even from Green’s dominant 2017. To the data:

Good grief, those 2019 numbers. But leaving those aside, there are interesting data points there in both 2017 and 18, when Green was extremely effective: hard hit % and exit velocity. What those graphs show is that it was really, really hard to make contact against Green but when batters did, they tended to hit the ball fairly hard. His fastball was just so overpowering that it generated a lot of swings and misses, and its spin-rate was so high that it looked even faster than it was.

As Mike has said repeatedly, though, when you only rely on a fastball at the Major League level, batters will eventually start to square you up unless you can keep them honest. That’s why Green dropped off a bit last year. This year, Green hasn’t been able to get the fastball by anyone: he is striking out only 11% of batters compared to about 35% in the last two seasons.

That means more batters are making contact, and, as we’d expect, hitting the ball hard. They’re waiting for the fastball. Hopefully, that’s just a small-sample-size, early-season noise—but as the earlier chart showed, his velocity and spin-rate are trending downward since 2017, in concert with his effectiveness. That trend has continued this year, but I didn’t include 2019 figures because it’s still way too small of a sample to really matter. With that said, however, it should be clear by now how troubling these trends are for a guy with Green’s arsenal.

A Way Forward?

All is not lost, however. Again, it’s extremely early in the year, with the Yankees playing in some cold, rainy conditions recently, including his rough appearance last night. Maybe Green’s velocity increases as the weather warms up and it gives him that extra edge again. That’s just Something To Watch for now, as is his ability to generate swings and misses at the top of the zone.

But what if the velocity doesn’t come back? In that case, it’s going to be extremely important for Green to develop a secondary pitch that is there for more than show. Even in its diminished state, his fastball is an above-average pitch. He can be a very effective reliever and a key part of the Yankee bullpen with it, but that will be considerably easier with a pitch with movement, so keep an eye on that splitter. If batters start biting, that will be a good sign for Green and the Yankees in the long-term.

The problem is that he’s never been able to develop that pitch before in his career, and his MLB success has always been buoyed by his fastball. Given the depleted state of the roster and general ineffectiveness of the bullpen so far in 2019, the Yankees had better hope that’s about to change.