Which Pitchers Got Lucky in 2015 (And Which Didn’t)

One of the biggest sabermetrics advancements was Voros McCracken’s DIPS Theory. If you’re familiar with DIPS, feel free to skip this paragraph while I get others up to speed. In 2001, McCracken theorized, and then proved that pitchers do not have control over balls hit in play. It was an incredibly radical theory that received very tough reception, yet it has stood the (albeit brief) test of time. Under his theory, the only events pitchers have control over are home runs, walks, hit batters, and strikeouts. This led to the creation of Defense Independent Pitching Statistics (DIPS). One such statistics is Fielding Independent Pitching (FIP), which is calculated as follows:

Screen Shot 2016-03-18 at 1.58.51 PM.png

The final term, C, is a constant that ensures FIP is on the same scale as Earned Run Average (ERA).

Based on the knowledge that ERA and FIP are on the same scale with the only difference being ERA’s inclusion of balls in play, I thought I would compare the ERAs and FIPS of last year’s pitchers to see who got lucky, who didn’t, and how the CY Young award did (or didn’t) take this into account. This is also a good predictive study because pitchers whose ERA varied greatly from their FIP will likely see regression to the mean this season. Analysts who aren’t sabermetrically savvy will be amazed by these so-called comeback seasons or shocking deteriorations, but it will all be a result of their luck on balls in play.

For a full list of players’ FIPs and ERAs from last season click here. Note that I only took into account pitchers who threw at least 100 innings.

Below is a look at the luckiest, and unluckiest pitchers from last season. 25 of 70 AL Pitchers and 19 of 71 NL Pitchers (min 100 IP) had a FIP that was 0.5 or more different from their ERA. I also included a column at the end of the table that gave their Batting Average on Balls in Play (BABIP), which should explain the FIP-ERA discrepancies.

Indicates CY Young finalists

Indicates CY Young Winner

Most/Least Lucky

American League

Lucky

Screen Shot 2016-03-18 at 6.07.09 PM.png

Unlucky

Screen Shot 2016-03-18 at 2.51.01 PM.png

National League

Lucky

Lucky NL

Unlucky

Screen Shot 2016-03-18 at 6.06.21 PM.png

There are many reasons for players to experience changes in performance other than chance, but analysts often mistake simple BABIP regression to the mean for a more far-fetched explanation. Don’t be surprised if this year’s story lines include players under the “unlucky” column making an amazing comeback because they started drinking fortified smoothies before games and regressions from players under the lucky column for other irrational reasons.

*A quick note about R.A. Dickey: One of the known exceptions to the DIPS theory is knuckleball pitchers. They are thought to regularly induce more outs on balls in play than normal as a result of their knuckleballs—which players roll over or pop up. I wouldn’t classify R.A. Dickey as lucky and would assume his ERA is actually a better indicator of his performance.

Best Pitchers Disregarding Luck

American League

Screen Shot 2016-03-20 at 6.55.10 PM.png

National League

Screen Shot 2016-03-20 at 6.55.53 PM.png

No love for Clay Buchholz who had the best FIP in the American League but didn’t receive a single CY Young vote. Unsurprisingly, he was the 11th unluckiest pitcher in the American League, sporting a BABIP of .329 which was 36 points above the league average.

While it isn’t exactly pertinent to this post, I compiled a list of the worst FIP performers from last year. Click here to see it.

Cy Young 

American League

Screen Shot 2016-03-20 at 6.56.33 PM.png

Ranks are out of 70 with 1 being best/luckiest and 70 being worst/most unlucky

Look at the top 3 AL finishers: Keuchel, Price, and Gray had very good years. That said, they all had worse FIPs than Chris Sale and yet better ERAs. Archer also had a better FIP than the top 3. Yet, he too had the highest ERA of the bunch.

National League

Screen Shot 2016-03-20 at 6.57.17 PM.png

Ranks are out of 71 with 1 being best/luckiest and 71 being worst/most unlucky

Now look at the top 2 NL finishers. Arrieta and Greinke both pitched very well, but they also both got really lucky. Kershaw outdid both of them in FIP. Greinke was even outdone by Cole and deGrom—the latter of whom received less than 5% as many voting points.

**Wade Davis and Mark Melancon both pitched fewer than 100 innings last season so they do not have a FIP or Luck rank.

Is BABIP Really Random?

You may be skeptical of DIPS and think these players performed better on balls in play because they’re better pitchers. Have a look at how the lucky CY Young finalists we just discussed performed just a year earlier on balls in play. Players go from left to right as given in the upper left box.

 

Is BABIP Random

Every single player performed worse the year before and two (three if you round Keuchel up 0.001) even performed worse than the league average in 2014.

Predictions for Next Season

Expect strong seasons from players who had low FIPs. Also expect many if not most of the players who had very good or very bad luck to reverse that. This doesn’t mean lucky players should be unlucky and vice versa, but rather their BABIPs should be closer to the league average.

When it comes to the Cy Young, players with low FIPs should be finalists. However, winning the award may have as much to do with luck as with skill. In that regard, maybe it is better to be lucky than good.

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