It all starts with a pitch. The lonely pitcher sits on his mound and throws a ball towards a hitter. That pitch could turn into any number of things and whatever happens will be pinned on the pitcher. For roto purposes, we're interested in a few statistics which come out of a pitchers performance on the mound: ERA, WHIP, K's, Wins and Saves. A pitcher throws a lot of pitches in a year and sample sizes help reduce the influence of luck but it still plays a major factor in anything beyond a strikeout or a walk from a pitcher. Identifying luck and evaluating past statistics helps us better predict a pitcher's future performance which makes us smarter fantasy baseballers.
ERA is a fickle mistress that is much more cruel than any other statistic because a pitcher can pitch like a champion but his ERA may still stink (see Zack Greinke 2011). If more batted balls become hits than expected or if more flyballs become home runs than expected then the pitcher's ERA is going to be affected. In Part 1 of my series of posts on how to evaluate pitcher statistics, we're going to focus on how to evaluate a pitcher's ERA in a given season.
Luckily, you don't need to break out your scientific calculators or look for one of my Google Doc spreadsheets to find all of these stats in one place. Fangraphs has these all hosted on their leaderboards under the Advanced tab. Go ahead and sort to your heart's delight to see which pitchers should be better or worse moving forward than their stupid ERA indicates.