2021 MLB Draft Guide: Ballpark Factors

The 2020 season was certainly an anomaly. The shortened season led to numerous postponements and no fans in the stands. It also gave us just 60 games for each team with lengthy postponements for some organizations. We also saw the Blue Jays play their home games in Buffalo, while the Texas Rangers introduced a new ballpark entirely (less than 1,000 feet from their previous home). If you’ve read previous Draft Guide content, especially the player profiles, you know that our staff has pulled data from the 2019 season in addition to 2020’s data as well. That’ll be similar to this piece but pulling 2019 data will be different in the sense that the Rangers and Blue Jays played in different ballparks. And again, Toronto may open the season at their spring training facility in Florida. In that case, any ballpark data pertaining to the Blue Jays is a moot point. There are still some moving pieces searching for resolution. But the purpose of this article remains unwaivered. We will identify the best ballparks for hitters and pitchers with a little explanation as to why.

Globe Life Field

After its debut was delayed, the Rangers finally got to host teams in their new digs with Globe Life Field. Public reaction was mixed as the exterior was mocked for being uglier than concept renditions that were posted online. But overall, the park was received well once fans were given a look inside during the MLB postseason as Globe Life Field hosted the National League Championship Series and the World Series. The ballpark pays tribute to the organization’s history even in its dimensions. Check out the table below:

There are a few differences especially in looking at left-center field. Plus, the deeper fences in the park increase the area, but it’s not the area that is the biggest factor for Globe Life Field. Globe Life Park was a hitter’s haven at one point when the wind would blow in from the outfield and then basically it would get “turned around” and thrown back into the outfield and this would carry baseballs further. This was due to the stadium having a closed structure behind home plate and down the first-and-third base lines so the wind came in from the outfield, circled behind home plate and quickly made its departure.

But when they “opened up” that portion of the stadium up for an even more open-air environment the jet stream was taken away. The park still aided hitters quite a bit, but without the wind pushing fly balls a little further, the power numbers dipped a little.

The purpose of Globe Life Field was to offer an indoor, air-conditioned experience to draw more fans out for a baseball game. As someone who has previously visited Globe Life Park, the conditions were a bit uncomfortable. It was hot and humid, and there were very few seats that offered shade aside from those under an overhang. Globe Life Field solves some issues by allowing the Rangers to play games indoors in a temperate-controlled environment. The downside is that it could suppress offense, as we saw in a small sample size a year ago.

Globe Life Field graded out as a middle-of-the-pack park in terms of run production, but it ranked toward the bottom in terms of home runs. Playing indoors didn’t do the Rangers any favors as the team tied for 23rd in home runs with 62 and they were second-to-last in runs scored with 224. But for the sake of remaining objective, they didn’t even play a half-season so let’s get through a full season before we can extrapolate data that we can feel confident in.

The Toronto/Buffalo/Dunedin Blue Jays

The Blue Jays couldn’t play in Canada last year due to travel restrictions because of COVID-19. That’s a damn shame if any of them developed an addiction to poutine or maple syrup. They spent the shortened 2020 season playing in Buffalo. As of this writing, it’s still a little unclear where the Blue Jays will be in 2021. Obviously, they’d like to play in the Rogers Centre in Toronto. It doesn’t sound like they’ll be playing in Buffalo again so it comes down to Toronto or Dunedin, Florida. Dunedin makes sense because it’s where the organization’s Spring Training facility is. And if they play all year in Dunedin then the warmer, more humid conditions playing in Florida are still beneficial for offense. Remember, the Marlins and Rays play indoors due to the heat and humidity. If the Jays play in Dunedin a full season then they’ll benefit from the humid conditions that will make the ball fly further. After all they wouldn’t be the first Canadian team to make the temporary move to Tampa as the Raptors are tentatively playing their home games in Amalie Arena, home of the Tampa Bay Lightning.

What can we expect from TD Ballpark though? The dimensions aren’t anything noteworthy, but from home plate to the foul poles, we find a little more depth than most ballparks. It’s 333 feet to left field and 336 to right field. The surface is also just grass, not an artificial surface, so we may not see as much bounce or life from the balls if they aren’t flying out of the park in the summer. If the Blue Jays commit to Dunedin to start the year then that’s still decent considering it’s currently pretty warm in Florida. Why else do teams flock there and to Arizona for spring training? I won’t touch on what they did in Buffalo’s Sahlen Field since they aren’t returning, but as of a few weeks ago there wasn’t a solidified answer on the Toronto Blue Jays home for the 2021 season.

The Coors Field/Humidity Effect

Ballparks come in all shapes and sizes with different features making them unique. But we typically see the cream rise to the top in terms of the most hitter-and-pitcher-friendly ballparks.

Coors Field has been written up ad nausea so for the sake of sounding like a broken record we’ll keep this brief since I’ve made it a point for four straight years to touch on the Coors Field effect.

If you’re no stranger to this article in recent years, we always touch on the science of baseball and the air density. It’s truly no secret that players in Coors Field tend to provide more offensive statistics. Higher elevations lead to thinner air. When the air is thinner it is less dense. So, the ball naturally travels further. There is less drag and resistance on a baseball traveling through the air, so the ball will travel further. Now when it gets warmer and more humid, the air is even less dense. Water molecules weigh less than air molecules so the higher the humidity (AKA the more moisture in the air), the less dense the air becomes. Humidity and warmer temperatures typically help all ballparks in the summer, like Great American Ballpark (aka Great American Smallpark). However, when Coors was originally constructed, scientists actually believed it was the dry air, not the thin air that gave us the Coors Effect. So while us lowly humans feel heavier and stickier on a hot, muggy day the air is actually less dense. We just feel gross due to condensation hindering the evaporation of our own perspiration. So when you add moisture to already less dense/thinner air, you’re making a hitter-friendly environment even more of a launching pad.

Gosh Darn Humidors

When Coors Field first opened it was nicknamed “Coors Canaveral” as a reference to Cape Canaveral where NASA blasts rocket ships into space. For the Rockies and Diamondbacks, prior to humidors, the baseballs were a little drier and elastic because of the climate conditions. So, by storing the baseballs in a humidified environment, the balls lose the elasticity and actually become a little heavier. They don’t come off the bat as fast and they don’t travel as far or bounce as far.

When Coors Field introduced its humidor in 2002 there was a significant drop in home run totals. However, Coors Field still finds itself at the top of the offensive charts at the end of each season. If you look at Fantasy Alarm's Ballpark Ratings you’ll see that Coors Field consistently ranks toward the top in home runs and runs almost every single year. Even in a shortened season with a small sample size, Coors Field yielded the most runs per game. In 2020, it was first in runs but only 11th in home runs. In 2019, Coors was first in runs, third in home runs. In 2018, it was second in runs and seventh in dingers. In 2017, Coors Canaveral was first in runs, but 15th in home runs due to some uncharacteristically elevated home run totals at other parks. As you can see, despite the humidor, Coors is still a hitter’s best friend.

The same cannot be said for Chase Field. We’re now a few seasons into the Chase Field Humidor experiment and the results are pretty legitimate 

as of right now. When it was announced that Chase Field would be installing a humidor to store its baseballs, physicist Alan Nathan from the University of Illinois predicted a 25-50% drop in home runs. This proved to be a little on the higher side. In 2017, there were 215 home runs hit at Chase Field. In 2018, the first year with the humidor, there were 171 home runs hit, which is a drop in about 20.46%. In 2017, Paul Goldschmidt  slashed .321/.422/.591 in Chase Field before the humidor with 20 home runs and 61 RBI. In Goldschmidt’s final season with Arizona, and the team’s first season with the humidor, Goldschmidt slashed .238/.363/.420 with 12 home runs and 32 RBI in Chase Field. His first home run in Chase that year didn’t come until May 30th, nearly two months into the season. And for what it’s worth, in 2019 the home run total went back up to 207 in Chase Field, but due to the juiced ball there were at least 200 home runs in all but six MLB ballparks (Tropicana Field, PNC Park, Busch Stadium, Marlins Park, Kauffman Stadium, and Oracle Park).

Now Chase Field did see a bit of a resurgence in 2020 with almost ten runs per game in the truncated season. However, in terms of power it saw just 2.4 home runs per game which is relatively middle-of-the-pack. Regardless of the run production in a shortened season, it’s relatively clear that the installation of Chase Field’s humidor has done little to maintain Chase’s offensive output from yesteryear. According to an article from the New York Times, five teams (Arizona, Colorado, Boston, Seattle, and the New York Mets) utilized humidors during the 2020 season and it’s likely those same five teams (and possibly a couple others) will make use of them again in 2021.

Playing Indoors vs. Outdoors

A few years ago we did a deep dive into stadiums with retractable roofs. Currently there are seven baseball teams with retractable roofs: the Arizona Diamondbacks (Chase Field), Miami Marlins (Marlins Park), Milwaukee Brewers (Miller Park), Houston Astros (Minute Maid Park), Toronto Blue Jays (Rogers Centre… If they end up playing in Toronto), the Seattle Mariners (T-Mobile Park), and the Texas Rangers (Globe Life Field). Most of these teams have varying weather-related concerns for why they have retractable roofs. Miami and Seattle both have heavy rain concerns. Houston sits right on the Gulf of Mexico so humidity is a concern down there. Toronto and Milwaukee need roofs to accommodate for the colder months at the beginning of the year. We’ve already touched on Globe Life, but the Texas Rangers new stadium has a roof with indoor air conditioning. Lastly the Diamondbacks don’t suffer from the same concerns as the other teams, but intense heat in the summer is the reason for keeping the roof closed to keep the temperature comfortable inside for fans, similar to Texas.

For the most part, Chase Field and Minute Maid Park keep their roof closed. That’s not to say every game is played indoors. However, a majority of their games are played indoors and we should probably expect that for Globe Life Field. T-Mobile Park in Seattle closes the roof for a few games a year if it’s raining, but they keep the roof open if they can. Miller Park in Milwaukee and Rogers Centre in Toronto typically see more balance between indoor and outdoor games. In general, there’s a slight bump in offense when roofs are open and open-air can carry the balls a little further. The open-air games typically come more during the summer, but again it’s a slight benefit to the offense, but not terribly drastic.

Other Ballpark Renovations To Monitor

Plenty of renovations have taken place the last few seasons to try and increase or decrease offense in the game as pitchers have been vocal about Major League Baseball juicing the balls. Perhaps the biggest news that broke more recently is that the league would change its baseballs after the league saw record-breaking home run rates in 2019. Five of the six seasons with the highest home run rates have occurred since 2016. MLB has announced that they will make some slight modifications to the balls to reduce the distance travelled by one-to-two feet on balls hit at least 375 feet. It’s not a drastic change by any means, but for any ball caught on the warning track or any outfielder that makes a spectacular catch reaching over the wall, just know the announcers may allude to a change in the new balls.

But there are certainly teams that have made efforts to their stadiums to accommodate for more offense. In 2016, the Miami Marlins moved their center field wall in from 418-feet to 407-feet and they also lowered the outfield walls by three feet. Then again, prior to the 2020 season the Marlins again moved the fences in a second time. The center field wall came to 400-feet from 407-feet and right-center field came in from 392-feet to 387-feet. Now Marlins Park was once again a pitcher’s park as it was in the bottom five in terms of home runs and run production in 2020. Similar to the closing statement for Globe Life Field, let’s give the new renovations a full season so we can then make judgments on the park. The lack of offense could simply be due to the fact the Miami lineup just isn’t very good.

Oracle Park in San Francisco has been a pitcher’s park in recent memory because it faces the bay and gets wind blowing in. Plus it had some of the largest field dimensions in baseball and within the last two years they made cosmetic changes to the park, similar to Miami. The outfield fences were brought in from about five-to-eight feet depending on which fence you speak of. Left-center field was 404-feet deep, but now it’s 399. Straightaway center field now rests at 391-feet instead of 399-feet previously. Right-center field, the deepest part of the park, now rests at 415-feet instead of 421-feet. In addition to moving the fences in, they’ve also been shortened from eight-feet to seven-feet. With the new changes in the shortened season, Oracle Park ranked as a Top 13 ballpark for hitters. Let’s see what kind of data we can mine from this park featuring a full season with the renovations in play.

If you want to look closer at Ballpark Factors there are plenty of sites you can look at. ESPN and FantasyPros utilize their Park Factor metrics that set neutral parks at a baseline of 1.000, so any park with a metric over 1.000 caters more to hitters and if that numbers is below 1.000 then it lends itself to pitchers and defense. As you can see, they clearly have different ways of calculating their PF rates because they have drastically different viewpoints on the home run rates for Great American Ballpark. It’s not a huge deal, but it’s fine if they offer up different totals. I’m partial to Fantasy Alarm as you can see totals runs averaged per game as well as total home runs among other rates. Another useful tool is Swish Analytics which shows the outline of each park, the height of the outfield fences, the dimensions, etc. You can also see Swish’s interpretation of which parks feature more-or-less offense.

At the end of the day, we all know which parks to target for DFS. Coors stacks are always a thing. Cincinnati in the summertime is a hitter’s dream. Kansas City and Miami can be rough for power production. These tendencies and beliefs tend to level out over the course of a full season. And hopefully a full season is what we get.