Closers aren't born, they're made, and some are made late in their careers. The Pirates may have found a closer in Grilli, but they ought not hold on too hard or too long.
Whatever the faults of the Pirates' front office, and we've seen a lot of them on display this offseason, you have to commend them for realizing that closers aren't born, they're made. When the opportunity came along to ship an increasingly expensive Joel Hanrahan to the Red Sox (granted, they might have considered doing it before 2012), they took it and turned the job over to Jason Grilli.
Grilli is a tremendously interesting player who has reinvented himself in his mid-30s, going from a mediocre (at best) middle reliever to a strikeout machine. Best of all, he'll be doing it for a measly $7 million over two years and could also potentially be flipped next offseason.
Of course, that's only if he's successful. It's worth noting that while closers are made, they generally aren't made this late in a player's career. Many pitchers get saves in their mid-to-late 30s and early 40s -- in all, 26 players have saved 30 or more games in a season after turning 36 -- but incredibly few of them started saving games in that number at that point. Here are the late blooming closers of the last few decades:
The reason we've seen so few is twofold: First and foremost, teams tend to be biased towards players who already have the "proven closer" label. Fewer and fewer teams buy into the myth that closers are somehow magical creatures and that only a few players have "the ninth inning mentality," but it's far easier to continue using a player in a role/job in which he's familiar until he can't fill that role anymore, bolts via free agency, or is traded. Given the cachet that comes with the closer's job, it's also often easier to simply go forward with the status quo rather than upset egos in the clubhouse.
Second, closing is often a young man's game given there's such a premium placed on throwing hard. Obviously, as players age they tend to lose velocity, and closing has long been thought of as a role that requires a couple extra miles per hour on a fastball. When an established closer does start to lose some speed, they can often still point to their continued effectiveness and hold onto the job, but when middle relievers reach a point where they start to slow down, teams are more reticent to put them in.
To be honest, I don't think I blame them. Yes, there are many healthy and effective relievers in their mid-to-late 30s, but I think it's telling that the five relievers on the chart above have exactly five seasons with 30 or more saves between them. Saito managed to maintain a great deal of his value going forward (perhaps not coincidentally, he was a great closer in Japan before coming to the majors), but Weathers and Franklin both took big steps back and were out of the majors within two years, Billy Taylor was never really effective again, and we don't know how Rafael Betancourt will react in 2013.
If relievers are volatile, older relievers are nitroglycerin. While Grilli may very well be the answer in 2013, even if the Pirates finally break through into contention this year they'd be smart to just make someone else their closer next year and start the cycle all over.