For all Buster Posey‘s insistence that he will be the starting catcher on opening day, there is a strong undercurrent in the front office for moving him to first base — or maybe even third base, with Pablo Sandoval grabbing a first baseman’s mitt.
Buster Posey is a special player. You don’t need me to tell you that obviously — in his short career thus far, he’s played (for the most part), at an elite level. To date, he has 645 plate appearances in 160 games — roughly a full season of playing time, during which he’s hit .294/.353/.462 and amassed 5.1 wins above replacement. And he’s still only 24 years old, so he presumably has a ways to go before reaching his offensive peak.
The problem with moving Posey is that a major element of his value is positional: in other words, that he’s a catcher. And catchers that are above-average on both sides of the game, as Posey is, are very difficult to find/replace. It’s the basic concept of positional value, as explained here. A brief excerpt:
The concept is easy enough to understand. Different positions on the field require different skills to play, and some are inherently more difficult than others. Catcher is harder to play than left field, and shortstop is harder to play than first base. We can easily accept an argument for accepting less production out of certain positions as an acknowledgment that the pool of players who can adequately play said position is small.
Posey’s inherently more valuable as a catcher, merely because it’s a harder position to play. In fact, based on estimates by Tom Tango (chart), over the course of a full season (600 PAs), a catcher provides roughly 2.5 wins more in value than a first baseman (assuming all other factors — defensive, offensive, etc. equal). To put it simply, that’s the difference between Posey being an all-star caliber player, and Posey being a solid/average-ish player.
But it extends beyond that. Posey is a good defensive catcher. Small sample size — I know, but if you take his catcher defense rankings from 2010 and 2011 (which, again, is roughly a full season), he’s worth about +7.5 runs on defense (not accounting for game-calling/pitch-framing).
Perhaps most importantly though, Buster Posey wants to catch.
Look, I understand the rationale behind moving Posey from the catcher position. As a catcher, he’s a constant injury risk. But the fact of the matter is:
1) Posey’s collision was sort of a freak accident — in the sense that those injuries are relatively uncommon. (For the record, I believe MLB should address the issue of collisions).
2) The reason Posey’s special is that he’s a catcher, and he’s a good one. And by moving him from the catcher position, he’s stripped of a lot of that value.