Fixing the Rockies, a data driven approach: Part 1
The Coors Field Problem
The fact that Coors Field is a difficult place to play might be the only thing anyone outside the NL West even knows about the Rockies. MLB.com decided to write a whole article on how Vladimir Guerrero Sr. had to call Jr. to tell him about hitting at Coors Field. I imagine the conversation was pretty short. “The ball breaks less. Oh, and there’s less air.” “Thanks Dad”. To be fair, he did hit a home run so I can’t say it didn’t help.
Rockies fans see this all the time. Any monkey can swing a bat and hit at Coors Field, and therefore you can’t trust any stat from a Rockies player. Every home run hit gets an asterisk that the ball flies farther. When people debate if Francisco Lindor or Trevor Story is better, they don’t compare apples to apples. They pick Lindor season stats vs Story’s road stats as if that’s the true mark of a Rockies hitter. Larry Walker played for the Rockies for 9.5 of 17 seasons, therefore he shouldn’t be in the Hall of Fame.
On the flip side of the coin, pitching at Coors Field is the most dreaded activity in baseball. Pitchers have nightmares of their trips to Colorado. Kenley Jansen’s doctor even told him not to fly to Denver due to a heart problem he required surgery for this offseason.
This presents a unique problem for the Rockies that no other organization has The Rockies have to construct a championship team (which is hard enough for any organization) at altitude. I was born and raised here. To me the Colorado air is air. To others, this city is a challenge to live in. I’ve had family members come to town and take a rest at DIA walking to baggage claim. These are professional athletes, but the thin air has created several problems bound by the laws of physics.
To correct for the increased flight of the ball, the walls were moved back farther than any other park in baseball. This means that we have the most outfield area as well. More area means more hits means higher batting average. This why the Rockies have 10 bitting titles in 26 seasons . Once again, it’s not rocket science. But what does this mean as far as constructing a good baseball team? The answer lies in how the Rockies are able to adjust to the constant park changes.
To get a better sense of the Coors Field effect, we are now going to look at park adjusted pitching and hitting metrics, ERA+ and wRC+, for all teams home and away splits. We aren’t looking at how Coors affects the number of hits, we are looking at what happens when you play half your games in Denver.
First we have all MLB teams wRC+ for 2019 at home vs on the road and the difference between them.
|Team||Home wRC+||Away wRC+||Difference|
|Team||Home wRC+||Away wRC+||Difference|
These are sorted by the difference between each split. At the top there are a few teams that are actually better at hitting on the road, like the Indians who hit 16% better away from Cleveland, but majority of teams hit better at home. On average major leaguers hit 4.8% better at home. This is simply home field advantage. It’s larger for some than others and there are many factors that can affect these numbers such as fan support. At the very bottom of our list we have the two worst teams in the National League and the Astros. Such a tragedy the Astros only hit 14% better than average on the road, if only they could play at home more often where they are 36% better than average.
At the very bottom are the Rockies. The switch from altitude has been well documented. I’m not the first one to point this out. In fact this split gets worse as the season goes on. It’s hard to hit at Coors Field and adapt to nasty breaking pitches on the road. In addition the increasing split suggests players bodies are simply taking a toll from playing in Denver. The Rockies hit 24% worse on the road than they do at home (which also isn’t very good), which is the largest gap in the leauge. Overall they hit 28% worse than league average on the road.
Now let’s look at pitching
|Team||Home ERA+||Away ERA+||Difference|
|Team||Home ERA+||Away ERA+||Difference|
We’ve now flipped to the other extreme. The Rockies are now at the top of the list. They pitch 16% better on the road.
This is a huge swing.
The Rockies simultaneously get a huge road advantage when it comes to pitching, and a huge road disadvantage when it comes to hitting. And keep in mind, we have already taken Coors Field into account. This is not 16% better because Coors Field is better for offense, this is 16% better simply due to switching ballparks. But here’s the most interesting part: the pitching gap is significantly smaller than the hitting gap. The Yankees actually have the opposite problem. They have a massive pitching gap, but a small hitting gap. They may not pitch well on the road, but if you hit enough home runs against the Orioles it doesn’t matter than much.
Some might see where I’m going with this, but let’s take it one step further. Let’s take all of the data from the other NL West teams who play at Coors multiple times a season and then adjust to park effects. To make sure we have a large enough sample, I’m taking the data over the past 3 seasons.
|Team||Coors Field ERA+||Road ERA+||Difference|
|Team||Coors Field ERA+||Road ERA+||Difference|
First thing to address is the 53 from the Padres. This is mostly due to the high scoring series earlier this year. Rockies fans remember it as the worst weekend in the history of the team. Padres fans remember it as the best weekend in the history of the team. (Even though it was a 2-2 series split.) Even using 3 years of data, that series had so many runs the Padres really take a hit.
Here is the answer we’ve been looking for. We can see the effect Coors has on any team coming from sea level even when we account for the increase in offense. The Rockies may be 16% worse at Coors compared to anywhere else, but only looking at the Coors field effect to each team’s ERA+ we see that the Dodgers are 31% worse when they come from LA, the Diamondbacks are 16% worse coming from Phoenix, the Giants are 25% worse coming from the bay, and the Padres are a whopping 46% worse when they come from San Diego. It isn’t just increased offense, this is a systematic shock to anyone who comes to play in Denver.
A few things to address here. The Diamondbacks have the same gap as the Rockies between home and road (in the opposite direction). They already like pitching on the road, but they are 25% worse pitching at Coors compared to other road ballparks. Second, the Dodgers are still a much better team. They pitch much better at Coors Field than the Rockies do, but that’s because they have better pitchers. We are comparing a team to themselves to isolate the effect of coming to Denver.
I’ve been pointing out that we are taking park factors into account, but there is another story there. The park factors are an adjustment based on how much offense actually occurs at the park compared to the league average. There is more offense at Coors, but that comes from both the Rockies and the away team. When those are averaged, we get the total effect. Essentially what I’ve presented is what we see when we split that average. The park factor for the Rockies is large, but the park factor for opposing teams is enormous.
Why does this happen? Basically when we pitch at home, we get a home field advantage. The pitchers have more experience on what to do at home while the opposing pitchers don’t. We cheer for our pitchers and unless the Cubs are in town, we don’t cheer for theirs. This is why I pointed out our pitching gap is smaller than the hitting gap. Pitching at home comes with both an advantage and a disadvantage relative to other teams.
The exact opposite effect happens when we hit. When the Rockies go on the road they are already going to perform worse because hitting on the road is hard for anyone. But not only that, the hitters also do worse because they face better breaking balls. This is a double negative that compounds the opposite direction.
Pitching is the Rockies’ biggest advantage, hitting is our disadvantage.
We’ve often been concerned if someone can learn how to pitch here. It’s hard, but the data seems to suggest even though the ERA is through the roof, our pitchers have learned. And this is 2019 data, so it doesn’t really include the prized young pitching staff. This is the rag-tag group of backups with half a year of big league experience.
This does not mean the Rockies are good at pitching at home, it simply means they are better than anyone else. And the goal of a baseball team is to be better than everyone else.
Press the Advantage
This is a very fun find, but how does it help push the Rockies over the edge of where they need to be to compete? The whole reason I bring this up is because the Rockies need to do more than find a few players. No other team in baseball is concerned with where they play. A simple approach to winning more ballgames, independent from players or the number of runs we score, is to press your advantages and fix your weaknesses.
Let’s see if we can press our pitching advantage. This piece has the indication that pitchers just try stuff out and hope it works when pitching at altitude. Mastering the question of pitching at altitude should be something the Rockies have a patent on. They should have been looking at this 15 years ago. It sounds like the organization really hasn’t done much about it.
Now I don’t have the answer for you here. I promised you to identify problems and suggest data driven solutions. I’ve shown the problem, but right now there isn’t any data for a solution. Unlike launch angels and defensive shifts, no one else is going to solve this. The Rockies are the only ones who can. That requires ideas and testing those ideas.
Compared to everyone else, we are pitching pretty well at Coors. That doesn’t mean it’s a solved problem, it only means it isn’t our biggest problem. If I were running the show, I’d get all the analysts (we don’t have many), coaches, trainers, and executives in the same room, get out the expo marker and start writing down ideas. Maybe it’s throwing more curveballs? They break more than sliders so maybe batters will miss them more? Maybe it’s throwing more sliders because the difference between the road and home isn’t as large? Maybe you have an entirely different pitch for home and away? Maybe the trainers think the players should spend a half hour in an oxygen tent? Any idea is valid.
Then get the analysts to design tests to prove whether these techniques improve pitching at Coors Field. In order to do that, you are going to need a control group. This means trying an idea on 2 starters and not on the other 3. This means randomly selecting pitchers to try ideas, not just the chosen ones who you are counting on. The team has thought of ideas before. For example, after Aaron Cook came along the team tried getting a bunch of sinker ball throwing pitchers. The idea was that a sinker causes more ground balls and more ground balls are needed at Coors Field. It didn’t work. But the point is the team had a belief of what it thought was the right idea and never designed a test to confirm it. This is actually a common theme today. The front office and coaches believe what the team is without stopping to confirm or deny that belief. As I’ve said, other teams also have a belief about the Rockies. They are all beliefs and the team needs to be able to separate fact from fiction. Ideally this would have been done in the 2011-2015 days when we were losing a lot, but it’s never too late to learn.
I’d take a similar approach to hitting. It seems Nolan is taking some breaking pitches off the slider machine to get himself primed on a road trip. I don’t know how that took so long to try. Maybe they take longer batting practice? Maybe they bring up a minor leaguer not to be on the roster but just to throw some breaking balls to live hitters? I’ve already highlighted hitting is the Rockies’ biggest weakness. This needs to be fixed.
Let’s say the Rockies solve this to make us an average team on the road, meaning 4.8% worse than home. If our offense was 19% better on the road, we would score approximately 65 more runs per year. Referencing back to our Pythagorean W-L, that’s 6.5 more wins a season (this is also why 10 runs are considered a win when calculating WAR). That’s almost 7 wins right there. If we solved one single problem, we turn the projected 2020 team into a playoff favorite.
In reality, the effects of Coors probably won’t be solved to make us an average team on the road. They absolutely have to be improved, but I doubt we get 19% improvement. That’s okay, even if we can only improve by 10% on the road that’s 3 wins. While I can’t say how much one can really improve the offense on the road, I am going to assume we can get close to 3 more wins with a focused effort. This is without changing a single player. We still need at least 4 more wins and more if we can. After all we are looking for more than just a Wild Card spot.
Now, it’s time to get to the nitty gritty of just how these can be fixed. The next two articles will look at pitching and hitting separately. We’ll start with pitching.