When confronted with a question like this, it’s common for the masses to point toward traditional statistics when coming up with an answer: win-loss record, ERA, WHIP, strikeouts generated, and walks allowed. There’s no denying that these statistics are important with regard to how any pitcher’s on-field performance impacts their team, but we live in a day where traditional statistics like that only tell a small part of a story.
There are tons of advanced stats to pore over when evaluating a pitcher’s performance from any given period of time, but one of the best and all-encompassing ones around is Skill-Interactive ERA, also known as SIERA. According to FanGraphs, SIERA attempts to measure the underlying skill of a hurler. Unlike FIP and xFIP, SIERA doesn’t ignore balls put in play, and it also attempts to give a more accurate picture as to why certain pitchers are better than others. A good SIERA is just like a good ERA — the lower the better.
With that in mind, let’s see how much certain pitchers outperformed their SIERA throughout the 2018 season. The sample looked at includes 128 hurlers who tossed at least 100 innings this past year. In addition to ERA, SIERA, and the difference (Diff) being displayed, other statistics are available for comparison’s sake, such as strikeout rate (K%), walk rate (BB%), BABIP, and strand rate (LOB%).
It’s worth noting that calling these pitchers “lucky” doesn’t necessarily mean they didn’t earn the numbers they produced, or they didn’t actually have a strong season. As we’ll find out, there are a number of hurlers here that actually dominated. It just means they reached these heights based on a bunch of variables going in their favor, which is never a guarantee from year to year.