Baseball is a game governed partially by design. When you see teams like the Astros or Cubs win the World Series, you can almost convince yourself that people are actually in charge. You can almost believe we have a handle on this. And to an extent, we do; baseball as a sport isn’t entirely random. The most talented players often become the best players. Clubs with enough of the best players often become the best teams. What’s so hard about that? Find and develop good players, and the rest should take care of itself.

But there’s a dirty little open secret. And this isn’t about how baseball games can turn on the flukiest of events. That’s true, also, but I’m referring to player development. What we’re all led to believe is that scouts are out there looking for guys who could be good. Then coaches and experience mold them, and then, eventually, guys become successful. A quality major-league player is a triumph for an entire organization. That performance level, however, can be fleeting. Becoming good in the majors isn’t the end of the story. A player is also supposed to stay good. And there’s surprisingly little people can do about that. Talent gets ripped away, often by injury. Injuries can be cruel and hard to predict, yet in a given year they can shape the landscape of an entire league. They can alter a team’s very direction.

Recently, the Mets designated Matt Harvey for assignment. Tuesday, the Mets traded Harvey to the Reds for Devin Mesoraco. Harvey’s development was a triumph for the Mets, just as Mesoraco’s development was a triumph for the Reds. They represented the best of what could go right for a talented young player in the proper hands. Now they’ve come to represent the nightmares that baseball people have when they fall asleep. Harvey and Mesoraco were two of the best. They weren’t allowed to sustain.

Harvey, of course, might have a more difficult personality. His stubbornness and tabloid character have done him no favors, and Harvey the person contributed to Harvey the player being dropped in the first place. But it’s not as if Harvey simply partied his way into irrelevance. That overlooks the very important fact that his body has fallen apart. Harvey was a No. 1 pitcher before undergoing Tommy John surgery. Then he was again a No. 1 pitcher after undergoing Tommy John surgery. Then came the diagnosis of thoracic outlet syndrome. Then came the stress injury in his shoulder. Harvey’s ability has deteriorated, because his body hasn’t allowed him to pitch. At least, not in the way that he’d like.

Compared to 2015, Harvey’s average fastball is down a little under four miles per hour. His peak fastball is down a little over four miles per hour. In 2015, Harvey threw 89% of his fastballs at least 95. So far this year, that rate is 1%. Harvey could adapt, sure. There are good pitchers in baseball who still throw slower than he does. But he’s having to learn on the fly, with a body he no longer trusts. Few are the pitchers who might handle this with grace.

Mesoraco might not have reached the same Harvey ceiling, but in 2014, he blossomed into one of the best all-around catchers on the planet. Mesoraco aimed for the air before everyone else was doing it, and he started bashing home runs before the league-wide homer spike ever emerged. Mesoraco broke out in what was a down year for the league’s hitters, running a 147 wRC+, and he earned a four-year contract extension. This is the final year of the four. Over the span, Mesoraco has played in a total of 113 games.

Surgery on one hip. Surgery on one shoulder. Surgery on the other hip. Shoulder strain. Fractured foot. Mesoraco was eventually supplanted by Tucker Barnhart, because the Reds needed a catcher who could actually play. Since 2015, Mesoraco has batted 316 times, running a 65 wRC+ with a WAR of -0.2. He’s looking a little bit better now, but no one could regain that lost mobility. Injuries zapped Mesoraco just as he was reaching his peak.

Harvey for Mesoraco makes sense. It makes sense in the way that many change-of-scenery trades make sense. In New York, Harvey came to be a source of frustration, every lousy game reminding the team of what he no longer is. In Cincinnati, Mesoraco hasn’t frustrated in exactly the same way, but he was still there as a shell of his prime. Harvey and Mesoraco no longer served a positive purpose. They might now, in new places.

The Reds knew they could no longer trust Mesoraco. But he is a major-league catcher, who’s been good before, and Mets catchers rank 29th in baseball in WAR. Kevin Plawecki is still hurt, and Travis d’Arnaud is out for the season. Tomas Nido wasn’t cutting it. Jose Lobaton wasn’t cutting it. Maybe Mesoraco will cut it. It’s far easier for the Mets to see the upside. Mesoraco hasn’t frustrated them.

The Mets, in turn, knew they could no longer trust Harvey. But he is a major-league pitcher, who’s been good before, and Reds pitchers rank 30th in baseball in WAR. Their starting rotation also happens to rank 30th in baseball in WAR. Many of the Reds’ options haven’t cut it. Maybe Harvey will cut it. It’s far easier for the Reds to see the upside. Harvey hasn’t frustrated them.

The Mets are hoping for a half-decent catcher to fill a void. They’re in contention, see, and in order to remain in contention, they can’t afford to run out a daily black hole. On the Reds’ side, Harvey is a warm body, which might be enough. There’s no thought of contention here, given that the Reds are a disaster, but they probably figure there’s a non-zero chance Harvey figures something out and makes himself marketable in July. Mesoraco was never going to return a prospect. Harvey might. He probably won’t, but he might. And to whatever extent it actually matters, off the field, Cincinnati is more or less the opposite of New York. The Reds might think that Harvey will be more focused. I don’t know. Neither side is getting much.

That’s the ultimate take-home here, in a swap of two first-round picks. A swap of two former All-Stars, a swap of one guy who once got Cy Young support for another guy who once got a down-ballot MVP vote. Both Devin Mesoraco and Matt Harvey are still looking ahead to their 30th birthdays. They reached the very peaks they were always supposed to. Unfortunately, then, the story kept going.