Really, Grant Green is coming to Pittsburgh because that's where Oakland is headed next, but you know what I mean.

As a refresher, Green was the A's first-round pick in 2009, no. 13 overall, and was a hot prospect for a few years after that, ranking 52nd and 63rd in Baseball America's Top 100 before the 2010 and 2011 seasons. The problem was that in 2011, he slugged just .408 in Midland and reports on his defense started turning quite sour.

Midway through that year, the A's finally bit the bullet on the inevitable and moved Green off of shortstop. They tried him in center field that year, but 2012 saw this:

The positive side of this is the idea of Green as a super-utility player, a modern-day Tony Phillips, a west coast Ben Zobrist. The negative side is that he didn't play any particular position well enough to stick there and look like a real future option. Sure, left field suddenly got locked down by Yoenis Cespedes, so even if Green was The Man there, he'd never be Oakland's Man. And now that we've seen what Josh Donaldson can do, it looks like third is foreclosed for a while, too.

What that leaves, aside from shortstop, where the A's and every scout I've ever read have already decided that he can't play, and center, where he's no demigod, is second base, the classic position where ex-shortstops move. (Putting aside your burners like BJ Upton and Billy Hamilton, where it makes more sense to let them roam the pasture running down balls in the alleys.) You can forgive the A's for not making second base Green's permanent home in 2012: it looked like Jemile Weeks had that position on lock and there was no point shoving Green there if he wasn't going to displace Weeks anyway.

Then Weeks displaced himself by hitting .221/.305/.304 in the majors and still only finding a semblance of his groove in Triple-A this year, slashing .265/.382/.363. As I've said before, the on-base percentage is nice, but if someone can't even slug .400 (shoulder injury or no) in the Pacific Coast League, they're going to get the bat knocked out of their hands in the majors.

What that left at the big-league level was an Eric Sogard / Adam Rosales platoon (where Jed Lowrie is an everyday player who at least theoretically shuttles between second and short depending on whether Sogard (second) or Rosales (short) is his double-play partner). The A's have actually received good production from second base, but that's because Eric Sogard has a decent OBP and Jed Lowrie has hit the snot out of the ball. Adam Rosales is batting .200/.273/.331 and hasn't had a good stint in the majors since 2010.

You have to figure Rosales is gone. The A's like his defense, and he seems like a nice human being, but if he's going to hit that badly (.186/.258/.303 in 326 plate appearances over the last three seasons), then the A's will find a way to make room for the next guy, and Rosales+Green is redundant: two righty-hitting middle infielders with positional flexibility is one too many.

The interesting question is whether Green is coming to the A's to take Rosales's platoon spot (though presumably playing second base rather than shortstop) or to start every day and push Sogard to a traditional utility-man role that has him starting once a week and backing up all three infield spots in case of emergency. On the one hand, you don't typically call up a prospect to platoon. On the other hand, Green has really only this year reclaimed some idea of prospect status, and the A's don't have time to screw around—they're in this to make the playoffs, and while mortgaging your future entirely isn't necessarily worthwhile, the minor hit the A's could theoretically take from having Green's first exposure to the bigs be in a part-time role isn't the sort of thing that requires us to scream "FLAGS FLY FOREVER" to excuse the irresponsibility.

The report is that Green will be starting tomorrow, but that doesn't actually tell us anything: Jeff Locke, a lefty, is pitching for the Pirates.

I wouldn't mind Green being in the short fifth of a platoon for the rest of the year—it'll maximize his bat in 2013 and give him time to get acclimated before he has to deal with the grind and mental difficulty of every-day big-league baseball. I also wouldn't terribly mind the A's taking a shot at Green as the daily starter, at least for a little while. If he struggles, then a Plan B platoon is still available as a fallback option. If he hits, then he's off and running and while you feel bad for Sogard, who did nothing to lose the job, that's the nature of the beast. He'll still be a big-leaguer.

Either way, assuming Rosales is the victim, I'm happy about what I expect to be the 2013 effect: reduced defense at shortstop when a lefty is on the hill more than made up for by increased offense at second base during those games.

Two things are notable: first, left-handed pitchers account for about 30 of plate appearances in the major leagues in 2013, and almost exactly the same percentage of games started have been made by lefties (768 out of 2598); second, Rosales, who got 22 starts against lefties and 10 against righties, wound up with 46 percent of his trips to the plate coming against the latter, i.e. the tougher side for him. Even a platoon player, in other words, doesn't only face one left-handed pitchers—he just faces a disproportionate percentage of them.

Of course, I'll have to throw most of this out when we find out that Rosales is going to stick around and the A's are going to option A.J. Griffin to Sacramento instead, taking advantage of the off-day on Thursday to skip his turn in the rotation (which would come on Saturday the 13th) and then bring him back after the All-Star break, making the decision about what to do with Rosales, Sogard, and Green at that point. (Note that because a player does not use an option year unless they spend at least 20 days in the minors, Griffin would not even count as "optioned" in a sense unless the team left him in Sacramento through the 27th, and the A's will need him to make a start long before that point.) ((Note further that this isn't my idea: I saw Raj Dhillon raise it on Twitter and I liked the idea so much that I had to steal it.))