Monday afternoon, the Royals and A’s exchanged four players, and the most recognizable among them is also the least valuable. It’s one of those multiplayer trades that tends to be easy to ignore, and that’s made all the more true by the fact that the Royals have entered a down period, and the A’s might not yet have emerged from their own. But as I’ve repeated lately, every major-league move is interesting if you look at it long enough. And in this case, there are two notable players in particular. Two players who might be considered analytical standouts. Here’s the breakdown:

A’s get

Royals get

At first, you could interpret this as the A’s reuniting with a beloved slugger. It’s not so. Moss is likely to be dropped or flipped, and he’s only in here for the purposes of the Royals shedding about $5 million. From the A’s perspective, this is about landing Buchter, a much-needed lefty for the bullpen. For the Royals, they get to roll the dice on some pitchers. Fillmyer is the prospect. Hahn is arguably the more intriguing one.

I’ll start with Buchter, and the A’s. Buchter is already an unusual case, in that he’s nearly 31 years old, but he also has four remaining years of team control. The A’s have been looking for a relief-arming lefty, and they were recently turned down by Brian Duensing, who re-signed with the Cubs for less money than the A’s put on the table. You might ask, what’s the hurry? Are the A’s really positioned to add 30+ year-olds to the bullpen? To which I’d respond, it depends on how you see the incentives. The A’s are nowhere close to being as good as the Astros are. But a young core is forming, and the team just played fairly well down the stretch. I’d say the A’s are in the middle, with an eye on a wild-card spot. They’re close enough to think about winning, and besides, Buchter doesn’t have to be only a one-season add.

Buchter is an atypical one. Over 139 major-league games, he has a 2.85 ERA, to go with a 4.68 xFIP. How does something like that happen? Buchter is extreme, in the rate of fly balls he gives up. Last season, according to Baseball Savant, Buchter yielded baseball’s fourth-highest average launch angle. And here it might be possible to spot a pattern, because the A’s have also added Yusmeiro Petit and Emilio Pagan to the relief corps this offseason, and their launch angles just ranked eighth and first, respectively. It could be something, or it could be a coincidence. Maybe they simply added what they could add. But there are going to be a lot of fly balls, and there are going to be a lot of pop-ups. Even in the home-run era, being a fly-ball pitcher doesn’t have to be a bad thing.

To further support the idea, I used Baseball Savant to examine expected wOBAs allowed on batted balls. Two seasons ago, among all pitchers, Buchter ranked in the 88th percentile. Last season, among all pitchers, he ranked in the 99th percentile. Buchter has avoided hitting the barrel, and as much as that’s still considered something of a squishy skill, at least he has two years to point to. That low BABIP isn’t a total mirage.

Between the seasons, it seems as if Buchter exchanged some strikeouts for some bad contact. His stuff is still more or less the same, and he hasn’t lost any velocity, but there was just a meaningful difference in how Buchter approached right-handed hitters. On the left, Buchter against righties in 2016; on the right, Buchter against righties in 2017.

Most recently, Buchter decided to take a jamming approach. Compared to the year before, Buchter’s average pitch against righties shifted inside by a full six inches. And the result: Out of every single pitcher in baseball in 2017, no one had an average location against righties that was further inside. Ryan Buchter was number one. Armed with mostly fastballs and cutters, Buchter went after the handles, and forced righties to try to keep their hands in.

Buchter has run a low ERA with more strikeouts, and he’s run a low ERA with fewer strikeouts. I’d say that’s a reflection on the quality of his stuff, and the A’s might have him choose which approach he likes more. Buchter, basically, appears pretty solid, either as a strikeout pitcher or as a bat-handle pitcher. I don’t know which style he’ll use in the season ahead, but I expect him to use it in a lot of seventh innings.

All right, so, the return. Fillmyer, I know little about, but conveniently, our staff includes Eric Longenhagen. Here’s what he had to say:

Scouts like him as a #4/5 starter. Sits low-90s, averages about 92 but will touch 96. Works best when altering hitters’ eye level. Everything is hard. Firm low-80s curveball, mid to upper-80s changeup. Scouts prefer the curveball, think it could be above-average at peak. Has trouble with release point consistency but Oakland has made some mechanical changes here during pro development and this was a New Jersey JUCO shortstop until 2014, so there’s some late projection on stuff like command and sequencing. Athletic, fields his position well (duh, was a SS) etc. A 40 or 45 FV type depending on how willing scouts are to project on the command into this guy’s mid-20s based on his background.

Fillmyer will turn 24 in May, and his strong ERAs in Double-A have come without notable strikeout rates. As Eric says, he could end up as a fringe starter, a couple years down the line. It’s Hahn whose arm seems more electric. And that’s part of what makes him so perplexing. Allow me to give you a very quick summary.

Hahn reached the majors in 2014, and while his fastball hung around 91, he generated an impressively low contact rate. The next season, he gained about a tick and a half, yet the contact went up. The next season, he gained another two ticks, and the contact went up even more. This past season, Hahn’s fastball stayed around 94, yet the contact hardly recovered. Hahn, as a major-league starter, has gone from having below-average velocity to having top-fourth velocity, yet he’s oddly become more hittable, with mediocre numbers in Triple-A to boot.

He even comes with a curveball to dream on. Hahn’s curve in 2015 had the second-highest average spin rate in baseball. The next year, it was fourth, and last year, it was fifth. Hahn’s curve hasn’t changed shape, and it’s reminiscent of the curves thrown by, say, Seth Lugo, Collin McHugh, Rich Hill, and Adam Wainwright. It seems like the curve should be a better weapon than it is. It could be a wipeout pitch, but it just hasn’t worked.

The biggest problem here is probably injuries. Either injuries haven’t allowed Hahn to develop, or his pitching style and added velocity make him more injury-prone. In 2015, he hit the DL with a forearm problem. In 2016, he hit the DL with a shoulder problem. In 2017, he hit the DL with a triceps problem. While I’m all for teams betting on talent, since injuries are hard to predict, Hahn is clearly a health risk. And while he comes with his own four remaining years of team control, he’s also out of options, which is what made him more available now in the first place.

I am interested in Hahn as a gamble for the Royals, because they have the pitching-staff room, and he might be able to pair his sinker and curveball to become a fascinating long reliever. To say nothing of his chance to remain a starter. None of the results have been there lately, but the stuff is the stuff. Hahn is sort of a scouting grab. He’s a power arm with bad numbers. You can take that and give him some innings. The Royals weren’t going to have all that much use for Ryan Buchter, not given the team’s presumed direction.

If you’ve read this far hoping to see this declared as a good or bad trade for one of the sides, I don’t have such a statement to deliver. Though I’ve long loved Jesse Hahn’s arm, I don’t know why he hasn’t generated quality numbers in years. I can’t ignore the fact he’s been unreliable. Buchter, at least, is pretty decent now, and the A’s are talented enough to think about playing some competitive baseball. As part of this, the A’s are eating about $5 million, and that matters, too. But, say, have you looked at the state of the Oakland payroll?

For four straight years, the A’s have had opening-day payrolls north of $80 million. Right now, even after picking up Moss, the projected payroll sits around $58 million. It’s true the A’s are being phased out of the revenue-sharing system, and that will certainly have an effect, but the A’s have something like $20 million more to spend, if they want to spend it. If they’re looking to win, the rotation needs help. Alternatively, the A’s are poised to eat someone else’s bad contract, provided it comes with a prospect or two. Keep an eye on the A’s; they can do more, and they should do more. Taking Brandon Moss doesn’t hurt them very much.

The A’s are trying to claw their way back to relevance. The Royals are preparing to take another step back. The best arm traded is attached to Jesse Hahn’s shoulder, but that very same arm has had a few too many problems doing its job. Buchter’s been more steady, and he’ll join what the A’s hope will be a quality bullpen that goes seven deep. Of course that same bullpen is no sure thing. But then, it’s not as if the A’s can often afford to pick up sure things.