A few weeks ago, defensive metrics at Fangraphs had judged Curtis Granderson’s defense in center field to be more than nine runs below average. He’s shot up to under six below avegare. Recently, he was not a top-five MVP candidate according to fWAR. Now he is.
Did he save a bunch of runs or improve his defense in a few weeks? Not likely. But the landscape he’s measured against is constantly shifting, and his contribution is rated against that volatile context.
Jacoby Ellsbury, a center fielder so good that Boston shifted him to left field to make room for the 38 year-old Mike Cameron last year, is worth over 20 runs more than Granderson, and is now the fWAR MVP.
Let’s check in again at the end of the season and see how it shakes out.