From Fangraphs (http://www.fangraphs.com/blogs/index...d-dips-theory/)
Last year, Josh Beckett posted a 5.78 ERA in 21 starts, and his struggles were one of the main reasons the Red Sox missed the playoffs. This year, Josh Beckett has a 1.86 ERA in 14 starts, and his dominance is one of the reasons that the Red Sox have the best record in the American League. A look beyond ERA, however, shows that Beckett is the poster boy for why metrics like xFIP were created in the first place.