Yesterday in the comments, there was some discussion about whether the Pirates should trade Mark Melancon. It was a somewhat obvious idea, since the Pirates already have some track record of trading closers and getting good value for them, but it hadn't occurred to me, because in general I think the Pirates should be acquiring established, effective players right now, not trading them.
Melancon might be an exception, however. Trading Melancon wouldn't be like trading, say, Neil Walker. Good regular players are somewhat reliable and generally tough to replace. Good closers aren't. When the Pirates traded Hanrahan, they replaced him with Jason Grilli, who had been plucked out the minor leagues just a season and a half before. When that stopped working, they replaced Grilli with Melancon, who they'd acquired cheaply because he'd posted a 6.20 ERA in Boston. If Melancon were to depart, his loss would sting, but the Pirates could replace him with Tony Watson, or maybe even John Holdzkom, and do well at closer without him. They would have to make up for the talent lost in the bullpen as a whole, but again, the Pirates have shown that they can find good relievers like Hanrahan, Grilli, Melancon and Holdzkom for very little.
Then there's Melancon's salary. He made $2.6 million in his first year of arbitration eligibility in 2014, and he's going to get a significant raise this year because he had a very good ERA, plus lots of saves and holds. Those numbers aren't why he should get a significant raise, but they'll matter in the arbitration process. MLBTR's model projected that Melancon would make $7.6 million next year. (And by the way, that link points to my Pirates offseason preview -- you should check it out.) That number seems crazy, and it's probably the result of there not being many comparables who got 33 saves and 14 holds in one year. Melancon will almost certainly make less than that. But his salary next season is likely to be significant.
"Great, trade him!" a thrifty GM might say. Well, not so fast. The Pirates shouldn't part with one of their best relievers unless they can get good value in return, and a Melancon deal certainly shouldn't be primarily about dumping salary. In general, the Pirates need to be spending more money than they are, and there are worse ways to spend it than on a very effective player. But salary is a factor, and if trading Melancon is one component of an broader offseason strategy that involves signing Russell Martin and/or spending heavily to significantly upgrade elsewhere, the Pirates should consider it.
The question is whether they'll be able to sneak in another one of these McDonald/Lambo/Dotel or Melancon/Hanrahan deals. My guess is that teams will be more leery of such trades than they were even a couple years ago. At least to a degree, the market seems to have figured out that overpaying for a closer isn't the best idea, particularly when guys who throw 97 MPH now practically grow on trees, and you can just find your own Holdzkom (or Greg Holland, or Trevor Rosenthal, or Kenley Jansen), put him at closer, and do just fine.
Then there's this year's crop of free agents. In addition to David Robertson, who's going to get a ton of money, the market is also likely to include functional closers like Grilli (gulp), Koji Uehara, Rafael Soriano, Francisco Rodriguez and Sergio Romo, plus talented non-closers like Andrew Miller, Pat Neshek and Luke Gregerson who you might be able to use at closer if you wanted. Robertson and Miller aside, a lot of those pitchers are likely to receive more moderate salaries than they might have a couple years ago, too.
Melancon is better than many of those pitchers, but there are already more guys on that list than there will be obvious closer vacancies (and that's not even counting lesser options like Casey Janssen and LaTroy Hawkins). If Melancon is set to make, say, $5 million next year, he won't even be getting that much of a discount relative to what he would get on the free agent market. So given the choice between giving up good talent to get Melancon and paying him $5 million, and just signing someone from the list above, my guess is that most teams will try the free agent market.
And even that assumes that many teams will go out this winter specifically looking for a closer, which almost sounds like going to Radio Shack to buy a flip phone. Guys like Robertson will do fine on this year's market, but it's mostly because they're good pitchers, rather than because they're closers. So many good young pitchers picked up saves this year while making very little money (Hector Rondon, Jake Petricka, Zach Putnam, Cody Allen, Jenrry Mejia, Kevin Quackenbush, etc.) that specifically going out looking for a closer seems passe. And if you're the type who still wants a Proven Veteran Closer, Radio Shack has plenty of K-Rods and Sorianos and Grillis to sell you. The Pirates shouldn't rule out trading Melancon, but this offseason might not be the right time to do it.