Buster Posey played shortstop at Florida State, don't you know. When he was still a prospect, it was a tired-and-true gag to point that out every time someone mentioned that Bengie Molina was blocking him. There were some well-meaning people who legitimately wondered if he could make the switch back. The correct response was always to point and laugh at the stupid people on the Internet.
With that out of the way, here's a list of possible shortstops for the Giants, ranked in order of potential defensive value:
1. Brandon Crawford
2. Joaquin Arias
3. Marco Scutaro
4. Buster Posey
5. Pablo Sandoval
6. Santiago Casilla
7. Tim Flannery
8. Kensuke Tanaka
You could probably squeeze Hensley Meulens in between Casilla and Flannery, too.
This comes up now because it was another day, another error for Tanaka, and it's not like the errors are the biggest problem. His throws sail across the diamond like a VCR thrown by Conor Gillaspie. He soft-tosses the second baseman on double plays. The Giants wanted to find out if Tanaka can play shortstop. He almost certainly cannot.
Does that matter, though? Pretend the Giants liked him as a hitter. If they already have Arias backing up Crawford, do they really need to factor in Tanaka's defense at short? Here are all of the players who logged an inning at shortstop over the last 10 years, with the players who got more than 50 innings in bold:
2003: 3 (Aurilia, Perez, Ransom)
2004: 4 (Cruz, Perez, Feliz, Ransom)
2005: 4 (Vizquel, Cruz, Chavez, Dallimore)
2006: 5 (Vizquel, Vizcaino, de la Rosa, Frandsen, Feliz)
2007: 4 (Vizquel, Frandsen, Aurilia, Figueroa)
2008: 4 (Vizquel, Burriss, Ochoa, Bocock, Castillo) (!)
2009: 4 (Renteria, Uribe, Frandsen, Rohlinger)
2010: 3 (Uribe, Renteria, Fontenot, Rohlinger)
2011: 5 (Crawford, Fontenot, Cabrera, Tejada, Burriss)
2012: 2 (Crawford, Arias)
Feels like I should have complained more about Jose Castillo playing short for four innings. Dammit. Can't go back now.
When the Giants have a settled shortstop situation -- or at least, when they're not cycling through a bunch of options because they don't know what else to do -- they use two shortstops. When there's an injury, obviously, things change. But that shouldn't affect the decision to keep Tanaka, because if there's an injury, they can call up Nick Noonan, Tony Abreu, or Ehire Adrianza. To be perfectly honest, I would trust Scutaro not to swallow his cleats at short; he was a full-time shortstop in 2011, after all. The decision on the last utility infielder probably shouldn't have too much to do with shortstop defense.
A bigger issue has to do with Tanaka looking rough at second and the plate, of course. But that's another story.
Hopefully, the Giants aren't absolutely married to the idea of a third shortstop. Because if they are, I have a feeling we're on a space shuttle sailing straight into the heart of Wilson Valdez. That wouldn't be good for anyone.