For the past week or so, I’ve been kicking around the idea of writing about Justin Miller. Miller is a 31-year-old reliever, and, by the way, he’s pitching for the Nationals. Though he’s allowed runs in each of his last two appearances, he’s faced 43 batters so far, and he’s struck out 22 of them, without one single walk. Miller, last year, was bad in Triple-A for the Angels. Now he looks like he could be one of the more dominant relievers around. It’s too early to go quite that far, but, well, you know how relievers are. They can emerge or decline in the blink of an eye.

It’s possible that, in Miller, the Nationals have found something. He might turn out to be one of the keys to their season. But Mike Rizzo is also no stranger to making midseason bullpen upgrades, and you don’t want to end up counting on Miller to keep up the miracle. And so, Monday, Rizzo has moved to beef up the depth in front of Sean Doolittle. In the current era of baseball, it’s almost impossible to have too many good relievers. The Nationals got a new one from the Royals.

Nationals get:

Royals get:

I’m not sure there’s anything stunning here. Herrera was very obviously going to be available, as a contract-year closer on a terrible team. The Nationals are in the hunt, and the bullpen in front of Doolittle has sometimes been shaky. The prospect package seems to be light, but rentals generally don’t fetch a blockbuster. Herrera’s strikeout rate is only 23%. What surprises me more than anything is that this happened on June 18. It doesn’t surprise me that the Nationals would want Herrera for five or six extra weeks. It surprises me that, on so early a date, the Royals would settle.

Let’s make something abundantly clear: The Royals must like the package they’re getting, and this is already being sold as an expression of faith in their scouts. They know these three young players better than I do, and they know what the organization might be able to do with them. No, there’s not a Gleyber Torres in the bunch, but rental Herrera isn’t the same as rental Aroldis Chapman. Plus, prospect development can be uncomfortably unpredictable. This might work out just fine, and when the Mets traded rental Addison Reed last July, they wound up with three relievers. Is this really inferior to getting three relievers?

Reed, though, was moved at the deadline. Meaningful trades this early in the season are atypical, despite what the Rays and Mariners already pulled off. Even if teams know in the middle of June they want to sell, it tends to take the buying market more time to develop. There’s seldom any substitute for the urgency of the trade deadline itself. Should a buyer want to jump the market early, it stands to reason the team should pay a little more. You pay enough to convince the seller not to wait, or ask around. In Herrera, the Royals had one of the best relievers who would be available. Perkins started the season as the Nationals’ No. 7 prospect. Gutierrez was the No. 10 prospect. Morel wasn’t ranked. Not one of these three looks to be an impact young player.

I don’t necessarily think that means the Nationals ripped the Royals off. This isn’t laughable or anything. But I’d characterize the return as leaning light. Given the time of year, and given the extra usage of Herrera the Nationals are going to get, I would’ve expected the return to lean heavy. An expression of faith in the scouts, indeed. The Royals are happy enough they didn’t want to wait to see if they could get anything more.

We should talk about Herrera a little bit. He’s not going to be the closer in Washington like he was with Kansas City, but then, he’s been a setup man before. He thrived in the role, and, of course, he’s already had time on the biggest stage, pitching in consecutive World Series in 2014 and 2015. As you presumably remember, Herrera is a hard-throwing righty. He hasn’t generated quite as many strikeouts as you’d expect, given the quality of his stuff, but at least this year, Herrera has issued a total of only two walks. They were both issued in his most recent outing.

With a fastball, a breaking ball, and a changeup, Herrera has a full repertoire, and he maintains only a small platoon split. He’s not vulnerable against lefties, which so many other righty relievers are. This year, among relievers, Herrera’s contact rate ranks in the 64th percentile, which is fine. But his strike rate ranks in the 97th percentile. He’s a little behind Sean Doolittle, and a little in front of Ryan Madson. Herrera, in other words, is always on the attack, and even more impressively, if you just focus on strike rate with non-fastballs, Herrera is No. 1 on the list. He throws strikes with his breaking ball and his changeup, and that makes him extra dangerous. They’re not just putaway pitches.

Behold Herrera getting ahead with a breaking ball:

Behold the heater finishing the job:

If the Nationals have their druthers, their bullpen will now be able to go Doolittle — Herrera — Madson — Brandon Kintzler — Miller — Sammy Solis. There are other options to round it out, including Shawn Kelley. It’s a better unit for the playoffs, but it’s also a better unit when it comes to trying to get to the playoffs. A bullpen addition lightens the load on everyone. I don’t know if another team will acquire a better reliever. That might all come down to the price for Brad Hand.

On the Royals’ side of this move, perhaps Gutierrez is the major name. He’s a 23-year-old third baseman with a 100 wRC+ in Double-A. He’s been a shortstop in the past, so there could be some glove there, and Gutierrez has also reduced his grounder rate this year by nine percentage points, suggesting the 6’3 righty might be finding his pop. On the other hand, he has all of a dozen career professional home runs, and he has four times as many strikeouts as walks. He’ll turn 24 in a couple of months. He has a limited amount of time to improve.

I’m most interested in Perkins, a switch-hitting 21-year-old center fielder. Now, he’s a guy in High-A, and he’s slugging .290. Right there, that might be enough reason to write him off. Yet he appears to be developing into a plus defensive outfielder, and in March, our prospect report said his plate discipline was “nearly elite.” Perkins has always drawn walks, and I’ve come around to the idea that guys with good strike-zone control can have surprisingly high offensive ceilings. Perkins could become a regular if he can hit the ball with any kind of authority.

Morel is someone who’s just — he’s a 17-year-old righty with 3.1 innings in the Dominican Summer League. He could become nothing, or anything. He’s the exact baseball definition of a lottery ticket, a live arm with everything to learn. Check on him again in four years. Every player like this is certainly talented, but a team gets major-league value out of one for every several dozen or so. Think of Morel like a middle-round draft pick.

So the Nationals are better. The Nationals are better, and the Royals are worse, but the Royals knew they were going to get worse, whether it be today or in another few weeks. I would’ve expected a trade on June 18 to return some stronger prospects, but if the Royals figured there’s going to be too much deadline chaos, I don’t know how much the timing will ultimately matter. I thought someone like Herrera would get more in the middle of June, but not by a ton. All eyes will now shift to teams with movable relievers like the Padres, who might be more willing to hold out for more. Yeah, the trading season has started, but it might not be fully open.