The Trade Deadline’s Most Interesting Lefty

All morning long, on Twitter, I found myself wading through Zach Britton rumors. At seemingly any moment, Britton could be off for one of the top contenders, looking to stabilize the back of the bullpen. It’s not hard to explain Britton’s appeal — though his performance hasn’t been outstanding since returning from the disabled list, he still throws hard, and the sinker still sinks, so he looks close enough to the guy he used to be. Britton is good. If he’s healthy, he’ll get a lot of outs.

Britton’s a lefty. Of course, we just saw another prominent lefty reliever get moved last week, when the Indians added Brad Hand. I want to make it clear now that there’s a difference between “most interesting” and “best.” There’s a great chance that Hand will be the trade deadline’s best lefty. I just can’t help but search off the radar, and, to get to the point, I’d like to talk about Adam Conley. I don’t know if he’ll actually get moved by the Marlins, since he’s under club control through 2021, but I’ve seen enough rumors about Kyle Barraclough and Drew Steckenrider to believe it’s a possibility. A team in the Marlins’ position shouldn’t be hoarding relievers. And if a contender is looking for a bullpen southpaw, Conley deserves a serious look.

What we have here is a case of a bullpen transition. Conley once drew notice as an interesting starter, but his stuff and his numbers went backward. Over eight starts this year in Triple-A, Conley struck out just 14% of his opponents. The Marlins brought him up and made him a reliever. That strikeout rate has more than doubled, and there’s even more to keep your attention.

Consider, for example, that compared to last year, Conley’s average fastball has gotten faster by five and a half ticks. It’s by no means uncommon for a pitcher’s stuff to play up when he gets to work in shorter outings, but out of everyone with at least ten innings pitched in each of the last two seasons, Conley’s velocity boost is the biggest in the game, by a couple miles per hour. Just right there, Conley’s development is encouraging — where his fastball recently hovered around 90 or so, now it’s getting up to 95 and 96. You can’t always predict whose stuff will play up the most. Conley has taken to the one-inning stints.

So the fastball is better. Everything is harder, really. As a consequence, Conley’s contact rate allowed has dropped by 11 percentage points. Via Brooks Baseball, let’s focus for a moment on Conley’s fastball/changeup combination. Here’s how his career velocities have looked:

The changeup comes in almost ten ticks slower than the fastball. That gap hasn’t eroded. Yet there’s something else, something more promising. Look at these horizontal movements. It should be easy to spot the take-home message.

Conley throws one kind of fastball and one kind of changeup. In the past, it used to be that the changeup moved laterally a little more. Now, thanks to some kind of tweak, the average horizontal movements are virtually identical. As noted, the changeup is slower, and it drops about two or three inches more than the fastball, but with identical lateral movements, the pitches better disguise one another. The arm action is the same. The spin must look just about the same. Few pitchers are able to make their fastballs and changeups look so alike, and, related to this, Conley’s changeup already has a run value of +6.0. That’s currently one of the higher marks in baseball, even though Conley hasn’t even reached 30 innings. He’s only barely behind Chris Devenski.

Let’s say you’re not convinced by the run-value measures. Totally fair; those numbers can be noisy. I can tell you that, when Conley has thrown a changeup this season, opposing batters have whiffed 34% of the time. There have been more than 1300 different individual pitch types thrown by pitchers this year at least 100 times. That changeup whiff rate for Conley is tied for the highest for any pitch type in either league. It’s been one of the very most unhittable pitches. Rather unsurprisingly, Conley is coming to trust the pitch more and more:

That plot folds in the slider. Conley is indeed a three-pitch pitcher, and the slider is fine. I’m just most enchanted by how the fastball and changeup work together. Here are some clips from earlier today. Conley throwing a 1-and-1 fastball:

Conley following that with a putaway changeup:

Conley later throwing a 1-and-0 changeup:

And then a 2-and-2 changeup for an inning-ending double play:

Conley’s numbers are already good, as they are. He’s a lefty reliever who can retire both lefties and righties, and there’s no doubting the quality of his stuff, now that his velocity is surging. There’s just one more piece here that I think adds to the intrigue. What’s happened these last few months is that Conley has moved to the bullpen, which has allowed him to throw much harder. His changeup looks the best it’s ever looked, now that it’s effectively mirroring his mid-90s heater. But take a glance at how Conley has used his pitches, by count. You might see an adjustment that ought to be made:

Earlier, you saw a clip of Conley throwing a changeup in a 1-and-0 count. That’s something he hasn’t done very often. Nearly every pitcher throws a higher rate of fastballs when behind in the count, and nearly every pitcher throws a higher rate of secondary stuff when ahead in the count, but, for Conley, this looks like something to work on. He’s throwing his changeup with more confidence, and his slider is looking good, too. Conley could stand to be less predictable. He could presumably benefit from throwing fewer fastballs in classic fastball situations. Not only would batters have trouble keeping up; Conley’s fastball could become more effective. The changeup looks great. The slider also works. If Conley were to better randomize his sequences, he could look even better than he has.

Put it all together and you could have an impact pitcher. Already, Conley is a good bullpen southpaw, but there’s reason to believe he could be even better. Furthermore, he’s under club control for a while, and you could even make the argument that he’ll deserve another opportunity in the rotation next spring. He wouldn’t be the first failed starter to do better in a second chance. Maybe the bullpen gains would carry over. That’s for another day. There’s a good chance the Marlins wouldn’t be enthusiastic about trading Conley away — they might be thinking about him as a starter again, themselves. Alternatively, they could want to see where his bullpen development goes. Current contenders should want to see the same thing. Trading for Conley might not happen, and it’s not likely something that would happen for cheap, but anyone looking for help should at least think about it. Conley’s tapping into a massive chamber of potential.