Fangraphs, the site that thinks Patrick Corbin just had a season that was above replacement level.
By RA9-WAR he's an astonishing (though not if you've actually watched him this season) -2.0 WAR.
Still, I can't help but wonder what a more competent defense next season might make him look. All of the advanced ERA predictors have him pegged between 4.0-5.0 ERA. He's far from a good pitcher, but is it at all possible he's not as truly awful as he's looked this year?