[Mick]

8. A.J. Pierzynski (of all people).  Him, I don't get.  Apart from the fact that he was a crank, he was an average hitter (.739 OPS, .280 BA), and a terrible fielder (was in top five stolen bases allowed eight times, top five passed balls five times).  His only year with the Giants, he led the league in grounding into double plays, the only offensive category he ever led the league.  All-star twice in a 19 year career, silver slugger once.  4x as many passed balls as Posey.  Range factor below league average.

I agree that Pierzynski (together with Papelbon) is one of the weaker players on the ballot, although it doesn't really matter. But just out of curiosity, in what way does Range Factor measure a catcher's defensive ability?

It covers assists and putouts.  For catchers, strikeouts are credited to the catcher. Pierzynski is rated #65 over the course of his career.

[Mick]

8. A.J. Pierzynski (of all people).  Him, I don't get.  Apart from the fact that he was a crank, he was an average hitter (.739 OPS, .280 BA), and a terrible fielder (was in top five stolen bases allowed eight times, top five passed balls five times).  His only year with the Giants, he led the league in grounding into double plays, the only offensive category he ever led the league.  All-star twice in a 19 year career, silver slugger once.  4x as many passed balls as Posey.  Range factor below league average.

I agree that Pierzynski (together with Papelbon) is one of the weaker players on the ballot, although it doesn't really matter. But just out of curiosity, in what way does Range Factor measure a catcher's defensive ability?

It covers assists and putouts.  For catchers, strikeouts are credited to the catcher. Pierzynski is rated #65 over the course of his career.