From the description of the OLIVER projection system:

The WAR statistic for hitters, by the way, is based on both hitting and fielding. To evaluate the latter, I have developed a fielding system which is based on detailed play-by-play data (and yes, it will be updated weekly in-season).

So basically it’s a proprietary system and I have no idea how it works. But from the little I understand of fielding metrics, it’s a better sign to have three really good years than to have one spectacular year (like Nyjer the year we traded him). Given how much noise there is in the signal, more years is better.

The linked article notes that OLIVER’s fielding projections have a really wide spread (and that this makes Mercer look like a big-leaguer even if he can’t hit), but this goes along with a couple of other systems — read this article to see why there’s some reason to think systems like UZR and Total Zone don’t give a wide enough spread. Also for some sweet, sweet Jeter haterade.

(And thanks for the recs, guys.)