MLB Hall of Fame 2013: Larry Walker and home/road splits

One of the things about Hall of Fame voting season that’s really irked me lately is the lack of support for Larry Walker, whose case has been summarily dismissed on the basis of his home/road splits. Walker played most of his career (10 of 17 seasons, to be exact) with the Colorado Rockies, and his numbers were accordingly inflated. There’s no denying that. You’ll be hard-pressed to find a more friendly offensive environment than Coors Field during the Steroid Era. In assessing Walker’s candidacy, it’s important to look at his statistics in this context. I have no problem with that.

I do, however, have a problem with the common methodology that many Hall of Fame voters employ in dealing with this. Rather than look at park-adjusted figures, which are easily accessible through sites like Baseball-Reference and FanGraphs, writers take a different approach to this issue: looking at home/road splits. Walker’s home/road splits, in particular, exhibit a fascinating symmetry:

Home: 1.068 OPS

Away: .865 OPS

Overall: .965 OPS

Now, the question becomes what to make of this. For a lot of voters, the away numbers seem to represent "neutralized" numbers -- what the player’s stats would be without park factors getting in the way. That appears to be the implication in Scott Miller’s reasoning, for example:

Larry Walker: Very, very good player. I'd take him on my team. But his home/road splits during all of those Rockies seasons in Coors Field were so uneven.

I have a few problems with this, and they are as follows:

-- The league, as a whole, tends to hit better at home than on the road. In 1997 -- inarguably Walker’s best offensive season -- National League hitters posted a .762 OPS at home, and a .726 OPS on the road. This means that with most hitters, isolating their road splits will lead us to undervalue their overall contributions. And over a full career, it gets to the point where these hitters are severely undervalued.

-- Road splits themselves are not "neutral." Let’s look at Walker’s 2001 season, for example. While other NL hitters’ road splits will get a slight boost from whatever time they spent in Coors Field, Walker's will not. As a member of the Rockies, Walker instead spent a lot of time on the road in parks like San Diego, Los Angeles, and San Francisco, where he had 79, 67, and 62 plate appearances, respectively. These were three of 2001’s five most pitcher-friendly parks, according to FanGraphs’ park factors. So while Walker’s home stats are certainly inflated by park factors, we see the opposite effect -- to a lesser extent -- with his road stats.

-- Home/road splits vary for reasons other than park factors.

-- The voters are inconsistent in applying this methodology. I’ve seen home/road splits cited countless times in arguments against Larry Walker’s case for the Hall of Fame, but rarely if ever have I seen them cited in discussions of Jeff Bagwell’s candidacy. If you’re going to whip out home/road splits in dismissing the case of a hitter who spent a lot of time in a hitter-friendly park, why not do the same with a guy who spent a lot of time in a pitcher-friendly park?

Park factors are imperfect, but if your goal is to adjust for ballpark effects, they’re a much better route than home/road splits (for the reasons I’ve outlined). The neutralized stats on Baseball-Reference have Larry Walker at a career .909 OPS. That’s significantly better than his road OPS of .865, and over the course of a 17-year career, this makes a world of difference. By my own crude back-of-the-napkin estimations, treating the .865 OPS as the "true" Larry Walker -- instead of the .909 OPS -- costs him about 15 wins. In other words, it’s reckless and irresponsible. Walker should be a no-brainer for the Hall of Fame -- there’s no question in my mind that he’s got the combination of peak and longevity to meet Hall of Fame standards. But sadly, this gross misapplication of home/road splits is putting a sizable dent in his Hall prospects.