It took the Mets until the day before camp closed to settle on a mix of relievers. One wonders exactly what they were looking for in their final Spring Training games, since one of the guys they chose for their big-league bullpen, Sean Green, allowed four runs in 2/3 of an inning on Saturday. Whatever. Here we go:

The Major League bullpen in April: Green, Francisco Rodriguez, Pedro Feliciano, Fernando Nieve, Jenrry Mejia, Ryota Igarashi, Hisanori Takahashi.

Overview: In my senior year of college, I prepped a jazz-composition portfolio for credit. At the end of the semester, I sat down with the music department chair to review my finished material. He listened to the tracks I had recorded and hummed through the charts I had written.

“Inspiration — A; execution — C-minus,” he said.

I had good ideas, he explained, but it was clear I had bungled and botched and half-assed them all. He was right. I was a senior in college, after all. The work was done in a haze and a hurry.

Maybe you see where I’m going with this.

The Mets took precisely the right approach to building a bullpen in the 2010 offseason. They scoured the international markets, found upside arms on the scrap heap, identified useful internal options including converted starters, and avoided blowing resources on pitchers with closer pedigrees like they did the year before. Inspiration — A.

Then, once that collection of potentially valuable bullpen arms was in house and it came time to settle on the right crew for the Major League relief corps, the team proceeded to blow just about every decision it faced. Execution — C-minus.

Apparently blinded by sunk costs, the Mets opted to keep Ryota Igarashi and Green around, even though neither could get the ball over the plate consistently in Spring Training.

Apparently unconcerned about uncertainty in their rotation, the Mets opted to waive Nelson Figueroa rather than hand him a bullpen role, risking losing him to another team or Japan even though he likely represented their best option to replace the first starting pitcher to fall victim to injury or ineffectiveness.

Apparently unconcerned about the fact that three members of their Opening Day bullpen have never thrown a Major League pitch, the Mets reportedly will not force Kiko Calero to report to Triple-A Buffalo, even though, by all accounts, Calero needed only more time to strengthen him arm this spring, and even though Calero is a veteran of 302 2/3 excellent Major League innings, and even though he’s coming off a season in which he posted a 1.95 ERA.

And then there’s the Jenrry Mejia thing. I’ve said my thing on that thing. I refer you to this, this, this, this, and this. I’m kind of sick of shrouding the kid in negativity because he’s a homegrown prospect and I root for homegrown prospects, and now I’ll be rooting like hell for him to dominate in his bullpen role.

The funny thing is, so many people act — and I’m certainly guilty of this myself — as if it’s sort of written in stone that he will. There’s no arguing that he looked great in the Grapefruit League, but 17 innings of Spring Training ball and a rousing endorsement from Jerry Manuel do not necessarily portend Major League success. Big-league hitters — not to mention big-league scouts — are really, really good, recall, and I wonder if Mejia might start looking more like the guy who posted a 4.47 ERA in Double-A last year after the league has seen him a few times.

And then I wonder, of course, if that could ultimately be a ticket back to Binghamton for Mejia, and so a blessing in disguise. And that sucks. This has got to be one of the weirdest fanbase/management divides of all time. I don’t think I’ve ever heard of any team’s fans putting up a more or less unified front urging patience and restraint against a front-office that seems to want no part of it. That’s why you never want your GM making decisions from the hot seat, I guess.

To make matters worse — or perhaps more ridiculous — the going sentiment among Mets fans and the media seems to be that the two sure things in the team’s bullpen are Rodriguez and Feliciano, and I’m not certain either will be that in 2010. The downright existential finish to the Mets’ 2009 campaign helped cover up K-Rod’s miserable second half. The well-compensated closer posted a 6.75 ERA with a 1.42 WHIP after the All-Star Break, and his rate stats in 2009 showed a continuation of career trends toward fewer strikeouts and more walks.

Feliciano, the reliable lefty specialist, could become way less reliable if the Mets make him less of a lefty specialist.

That leaves Nieve, a righty who pitched well — albeit far above his peripherals — in limited innings for the 2009 Mets, and Takahashi, a deceptive lefty long-man who appeared dominant at times in the Grapefruit League. Like Mejia, both are talented mysteries yet to prove they can consistently retire Major League hitters.

Could the Mets’ bullpen succeed? Absolutely. Perhaps K-Rod’s rough second half was just a function of the Mets not being in the pennant race, and Feliciano’s improved cutter will make him more effective against right-handers, plus Takahashi will continue to daze hitters like he did in Spring Training, Nieve will pitch to the potential that made him a top prospect in the Astros’ system, Green and Igarashi will work out their mechanical kinks and Mejia will be every bit as good as advertised and become the dominant eighth-inning guy the Mets seem to want him to be, development be damned.

And in all likelihood, at least some of those things will happen in 2010. All of them won’t, though, and the way the Mets so brazenly went about casting aside their best contingency plans could cost them in time.

The Major League bullpen in September: I’m not even going to try.

How they stack up: This is an exercise in futility, just like attempting to figure out who’s going to be in the Mets’ bullpen in September. There’s so much uncertainty and fluctuation in every bullpen every year that I shouldn’t even try. I’d joke that the Phillies got a head start because Brad Lidge will open the season on the Disabled List, but there’s a reasonable chance Lidge will be awesome again this year. That’s just how it goes.