How Significant are A-Rod’s 3,000 Hits in MLB Betting?

Posted by Alex Murphy on July 8, 2015 in

Reports of the demise of Alex Rodríguez as a productive player in Major League Baseball (MLB) appear to have been greatly exaggerated. After he was suspended for the entire 2014 season for using performance-enhancing drugs, most discussion of the 39-year-old focused on whether the New York Yankees would find a role for the former superstar, or simply pony up the $61m they owe him and cut him from the team. But Rodríguez has stunned the MLB betting world with a hot streak that has made him the American League’s seventh-best hitter over the season’s first two weeks. And on April 17th, he generated the first headlines related to his on-field performance in years, by crushing a high, outside fastball for the longest home run anyone has hit so far in 2015. The high-arcing shot flew 477 feet (145 metres), before landing on the concourse behind the lower deck of left-field seats in Tampa Bay’s Tropicana Field.

Taking a Look at How Significant are A-Rod’s 3,000 Hits in MLB Betting

Observers familiar with the unreliable nature of baseball statistics over short timeframes will surely warn that expectations for Rodríguez need to be kept in check. Robert “Voros” McCracken, an early and influential quantitative analyst of the sport, once memorably wrote that any MLB hitter can do just about anything, good or bad, in a mere 60 at-bats (a little over two weeks of play). Countless players have hit four home runs in a span of 35 at-bats or less, as Mr Rodríguez has so far this year, and gone on to achieve little. In 2006 the long-forgotten Chris Shelton hit nine homers in his first 51 at-bats. He mustered just seven more longballs over his remaining 322 at-bats that season.

However, the sabermetric canon also includes a caveat to “Voros law” about the volatility of small sample sizes. Although the overwhelming majority of events that can transpire in baseball over a brief time period cannot be distinguished statistically from random variation, a handful of accomplishments are so rare that even a single game can contain impressive predictive power. Bill James, the father of modern baseball analysis, called this principle “signature significance”. In one well-known example, of the 14 pitchers who have struck out 18 or more batters in a nine-inning game during the past century, 12 were at least All-Stars, and six are in the Hall of Fame. Rodríguez’s mammoth blast might well be a similar case. After all, of the 38,143 homers hit in MLB since 2007—the first year that Hit Tracker recorded the path of every ball to leave the yard—just 25 (0.06%, or one in 1,525) traveled 477 feet or more.

Have Other Players Been Able to Impact MLB Betting Lines as Rodriguez?

The group of 22 players who have hit a homer of at least 477 feet over the past eight seasons is extremely impressive, and would approximate any fan’s shortlist of the most feared sluggers of recent vintage. It features 15 All-Stars, such as Mike Trout, the sport’s best player (who clubbed a 489-foot rocket last year), and Giancarlo Stanton, who is widely recognized as having the most raw power in the game and has met the 477-foot threshold twice. Other star hitters in this select club include Adam Dunn, Prince Fielder, Josh Hamilton, David Ortiz, Nelson Cruz, Justin Upton, Edwin Encarnación and Mark Teixeira. The rule is not completely foolproof: the disappointing Cameron Maybin once sent a ball 485 feet deep. But even some of the apparent exceptions turn out to support the trend. The name of Curaçao’s Wladimir Balentien might surprise most fans, since he never succeeded in MLB. However, his 495-foot shot in 2009 turned out to foretell his setting the Japanese league’s single-season home-run record in 2013.

Mr Rodríguez, who currently ranks fifth on baseball’s all-time career home run list, certainly fits in with this formidable company. But does his admission to this club merely burnish his long list of past achievements? Or should it also influence expectations of how he is likely to perform for the remainder of his twilight years?

In order to determine how much predictive power a single deep home run can provide, I started with every batter who played between 2007 and 2014. I first discarded all their ground balls and pop-ups, since balls on those trajectories cannot become homers no matter how hard they are hit. I then measured the share of their other batted balls—the line drives and outfield flies—that turned into home runs, a standard measure of a batter’s power. If ultra-long home runs truly have signature significance, then players who hit even one ball as deep as Rodríguez’s should fare well above average in this category over the course of an entire season.

Nonetheless, the logic of signature significance suggests that this know-it-all, hold-your-horses message is arguably just as simplistic as the irrational exuberance over early-season hot streaks it criticizes. The fact that Rodríguez propelled a single baseball 477 feet means there is a very strong chance he is not the player we thought he was. Guys who are washed up just don’t hit 477-foot homers. Not even once.