December 17th, 2012
Josh Hamilton is headed to Anaheim with his power left-handed bat. Let’s take a look at the motivation behind the Angels move and assess how he might fare in Orange County—or LA, as the Angels prefer to call it. On the positive side, the Angels get a double-hit by not only signing a top player, but stealing one from a division rival. It’s reminiscent of when the Yankees signed Johnny Damon away from the Red Sox and the Mets signed Billy Wagner, the former Phillie, both after the 2005 seasons. The Hamilton signing is a bigger, higher impact version of this effect. In terms of star power, this signing also helps the Angels battle the Dodgers for baseball supremacy in Southern California. Putting a contending team on the field and winning championships will likely ultimately determine which team is embraced by the most fans, but the star talent on each roster will also matter. The Angels add Hamilton to Trout, Pujols, Jered Weaver and company, enabling them to go toe-to-toe with the Dodgers’ marquee talent—Kemp, Kershaw, Greinke and Adrian Gonzalez.
A couple of things to recognize about Hamilton. First, he played in one of the most hitter-friendly ballparks for lefty hitters. The Ballpark at Arlington ranked 3rd in terms of the park factor for left-handed hitter home runs, while Angels Stadium in Anaheim ranks 23rd. Considering the 2013 schedules for both the Rangers and the Angels and the parks in which they play, Hamilton will play to a park factor that suggests about 20% less homeruns, than if he remained a Ranger. Another issue, which is perhaps more concerning, is Josh Hamilton’s track record against top-flight pitching. In a recent study, I segmented all starting pitchers into different levels of “quality”, based on the OPS they yielded over a season. I defined “top” pitching as the top 1/3 and “bottom” pitching as the bottom 1/3 of starting pitchers. (I controlled for the lefty-righty factor and I rated pitchers for each season in the study—2009, 2010, and 2011.) The average left-handed hitter has a spread of 182 OPS points in his stats against “top” vs. “bottom” pitching. In other words, a .732 OPS guy (MLB-wide average against starting pitchers) is expected to hit .641 against top pitching and .823 against the bottom third of starters. Josh Hamilton’s spread is far more dramatic. Instead of a spread of 182 points, his is 433 points (see chart below, from MLB Network’s Clubhouse Confidential).
Hamilton hit .721 against top pitchers, while banging out an OPS of 1.154 against the weakest pitchers. He performed only 12% above the MLB average against top pitchers, but a bone-crushing 40% above league average against the weakest third of the rotation. This suggests that Hamilton, who was a .909 OPS guy over these three seasons, feasts on weak pitching, but is neutralized by top pitching. Incidentally, this is a consistent pattern over the three years in our sample. Even in Hamilton’s MVP season of 2010, when he batted .359 with a 1.014 OPS, he exhibited the same pattern of hitting. In his MVP year he hit under .800 vs. top pitchers and over 1.200 against weak pitchers for another 400+ point spread. This has serious implications for the postseason, since the mix of pitching in the postseason closely resembles what we call the “top” pitchers. These pitchers represent one-third of regular season innings, but over 60% of postseason innings. Hitters who do not fare well against top pitchers are not as likely to get it done in October. Given the quality of the Angels’ roster, we may have a chance to see how this movie ends over the next several Octobers.