I don't know how Pittsburgh Pirates fans are going to react to the club trading closer Mark Melancon to the Washington Nationals with the Pirates just three games out of the second wild card, but I suspect not very well.
That's especially true when you consider that since 2013, Melancon has a 1.80 ERA and Aroldis Chapman has a 2.03 ERA and the Yankees got a high-upside shortstop prospect for Chapman, while the Pirates merely got reliever Felipe Rivero and his 4.53 ERA, plus minor league lefty Taylor Hearn.
The trade might smell of the Pirates waving a white flag, but that's definitely not the case. The Pirates give up a great closer, but they pick up a good reliever in Rivero, who has better peripheral numbers than his ERA indicates. More importantly, the Pirates trade an impending free agent who was unlikely to get a qualifying offer — as a small-market team, they wouldn't want Melancon to accept what is projected to be a $16.7 million salary, too high a percentage of the team's payroll for one relief pitcher. So they get a major league reliever who can step in and contribute and an interesting minor-league arm. With even the odds of winning the wild card fairly small, the Pirates didn't want to keep Melancon and then lose him for nothing in the offseason.
The key for the Pirates will be how the current relievers make transitions into their new roles — and whether they continue pitching the way they have in July, when the Pirates bullpen has a 2.03 ERA. Tony Watson presumably takes over the closer role with Neftali Feliz handling the primary setup role. Hard-throwing Arquimedes Caminero, Rivero and Jared Hughes handle the middle innings. Even without Melancon, it projects has an above-average bullpen the rest of the way. Pirates manager Clint Hurdle will continue to rely heavily on that bullpen, because other than Gerrit Cole, Pirates starters have been having trouble going deep into games.
If Watson does the job as closer and the setup guys keep spinning zeroes, this could have no impact on the final number of wins for the Pirates. If Watson blows three saves, then it's a trade that could obviously sting. It's also important to note that the Pirates are 9.5 games behind the Cubs and are playing for a wild card, not a division title, so going "all in" for 2016 doesn't make sense when you're just playing for a game in which the reward might be a one-game matchup against the Marlins' Jose Fernandez, Mets' Noah Syndergaard, Dodgers' Clayton Kershaw or Giants' Madison Bumgarner.
As for the comparison to the Chapman trade, that has to be considered an outlier, not a deal that suddenly set a new market for relievers. The Pirates weren't going to get a top-25 prospect for Melancon, even if the difference in value between him and Chapman is minimal.
The Nationals actually lead the majors in bullpen ERA, but Jonathan Papelbon's recent struggles created the desire for a reliable closer. Among the 24 relievers with at least 15 saves, Papelbon ranks 23rd in ERA, 23rd in batting average allowed and 18th in strikeout percentage. (Melancon, FYI, ranks 17th, one reason why Chapman is perceived to have so much more value.) Papelbon simply doesn't have elite closer stuff. In fact, he really should get shuffled deeper into the Nationals bullpen, and not just back to the eighth inning. Blake Treinen and Shawn Kelley have both pitched better and should get the higher-leverage roles.
For the Nationals, this deal is more about the postseason than needing Melancon to win the division. They already have odds of greater than 90 percent of winning the National League East. Considering there are rumors of Lucas Giolito for Andrew Miller out there, this deal for Melancon makes much more sense, getting a reliever of similar quality without giving up a high-upside prospect.