The Rockies Have Their Worst Coors Field Hangover Yet

The Colorado Rockies have always played their best baseball at home in Denver. Since joining MLB in 1993, Colorado has a .544 home winning percentage — the 12th-best of any club in baseball. This year, the team is 31-17 at its home park, giving it the sixth-best home record of any club, and it’s outscoring opponents by more than a full run per game there. Just last week, the Rockies showed off for the fans on Blake Street in an 8-0 rout of Pittsburgh, with pitcher Germán Márquez very nearly recording a no-hitter. 

But as we’ve noted before, away games have been a very different matter for the Rockies over their history — and this year is providing the worst road nightmare the franchise has ever experienced.

Remember that 31-17 record in home contests? Well, on the road, Colorado is just 6-32. That’s on pace for the worst road record in modern history, a staggering 488 (!) points of winning percentage worse than the Rockies’ success rate at home. Naturally, most teams win more at home than on the road, but a gap this large is historic. Pending the inclusion of data from the Negro Leagues, the Rockies are tracking for the most Jekyll-and-Hyde home-road split in winning percentage out of any MLB team since 1901:

In case you were wondering, that’s how a team 14 games above .500 at home still manages to find itself 13 games out of playoff position as we cross the midseason threshold of the 2021 schedule. 

And this year is hardly an isolated case. In contrast to that 12th-ranked record at home since coming into existence in 1993, Colorado ranks dead last in winning percentage on the road over the same time period, winning at a clip 148 points lower on the road than at home. That’s almost double the average team’s home-versus-road record differential, and nearly 50 points larger than that of the Pittsburgh Pirates, the team with the second-biggest gap. The difference between Colorado and Pittsburgh is roughly the same as the difference between the second-ranked Pirates and the No. 28 Mets.

Even when they’re not challenging all-time records, the Rockies almost always have a larger than average split between their home and road winning percentages. It’s happened 23 times in the 29 seasons they’ve played, including 16 consecutive seasons at one point (between 1995 and 2010). 

A huge differential in home-versus-away record isn’t necessarily a bad thing -- provided you can win a ton at home to offset all those losses on the road. But as is clear in the chart above, the culprit for Colorado’s big splits is far more often a poor road record (relative to the average team) than an excellent home record. In the typical Rockies season since 1993, their home winning percentage is just 3 points better than the average team, but their road winning percentage is 68 points worse.

So why does this keep happening to the Rockies again and again? It’s a complex problem to unpack because it cuts to the heart of park effects and other core tools in the sabermetric arsenal. Clearly, Colorado has to deal with a unique situation when it comes to its home park. The thin air of Denver makes it easier to hit the ball farther, which as a general rule helps hitters and hurts pitchers. Making matters even worse for high-altitude hurlers, it also reduces the movement on breaking pitches. But if park factors are properly calibrated, we can theoretically account for this by adjusting the statistics of players when they play games at Coors Field. And in home games this year, the Rockies appear to be a competent team even after correcting for home-field and park effects.

If we add a park adjustment to Baseball-Reference.com’s split OPS+ stats (which measure performance relative to league average within a given split), Rockies hitters rank 17th this season with a 99 OPS+ at home, while the pitchers are allowing a home OPS+ of 85 -- fifth-best in MLB, since a lower OPS allowed is better. But on the road, those numbers are significantly worse on both sides of the ball: Colorado’s hitters see their OPS+ drop by 36 points from their home rate, and its pitchers see their OPS+ allowed increase by 39 points. Both road OPS+ numbers place Colorado last in MLB:

That’s really just an exaggerated version of the Rockies’ typical story since 1993. On average, Colorado’s batters have historically been below-average at home (after adjusting for park), though they hit better than the OPS+ their pitchers tend to allow. On the road, however, they hit for an OPS+ 8 points worse than at home and allow an OPS+ 7 points higher, which leads to all those disastrous road records.

At this point, there are only a few plausible explanations for the Rockies’ persistent road woes. One could simply be that Colorado has bad players whose true talent is revealed by their poor splits away from Coors. But that would have to be true across decades of franchise history, including seven managers and three general managers,¹ and it would imply that the Coors Field park factors are fundamentally broken. Alternatively, it could be that the team-building attributes that lead to success at Coors also lead to failure elsewhere. Or it could be that the so-called Coors Field hangover effect is one of the most persistent (and least-discussed) disadvantages faced by any team in pro sports.

Indeed, there’s a lot of evidence that Colorado’s players are actually at a significant disadvantage on the road, most likely because of the difficult adjustment involved in going from playing mile-high baseball to trying to do it at sea level. And while it remains unclear what the Rockies themselves can do to remedy the unique drawbacks of their location -- certainly Colorado has tried plenty of Coors workarounds over the years, usually to mixed results at best -- MLB itself could implement changes to reduce the hangover effect in the name of competitive balance. For example, they could put more scheduling emphasis on starting Rockies road trips at medium-altitude parks to help ease the team into the changes it faces when leaving Denver.

Until then, though, the Rockies are usually going to face at least some version of what’s happened so far in 2021. Of course, this year’s situation is notably extreme -- we’re talking about a team playing to a 105-win pace at home and a 26-win pace (paging the Cleveland Spiders!) on the road. And Colorado has done itself exactly zero favors in recent seasons by trading away what seems like any superstar the team can get its hands on. But there’s also a good reason the Rockies face some kind of road disadvantage most years. The particulars of playing a mile high can often make the team look good at home, but the descent to lower altitudes on the road more than offsets those benefits -- and if you don’t believe it, just ask the 2021 Rockies how that’s been going for them.

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