When looking at statistics for players, a larger sample is preferred to a smaller sample. However, projection models weigh the most recent stats more heavily than those accumulated, for instance, three years ago. In other words, recency of stats matters, too. That idea can also be applied to ballpark factors as well. While a larger sample is good, it’s also important to see how a ballpark played most recently.

It’s possible that something changes from one year to the next that causes a stadium to play differently. For instance, maybe Wrigley Field experienced more days of the wind blowing in from Lake Michigan in 2019 and suppressed homers more last year relative to the three-year average. Maybe the weather was warmer for home games at Citi Field relative to prior seasons and the ball carried farther resulting in a higher park factor for homers in 2019 compared to the three-year average. While neither of those things may be true, both hypothetical situations illustrate how and why parks can play differently from season to season. Further complicating matters is the juiced ball MLB used last year. It remains to be seen what ball MLB uses this year, but if they continue to use what I’ve seen other pundits refer to as the “rabbit ball,” last year’s park factor data could prove more prescient for how parks will play this year than the three-year averages.

Below, I’ve laid out four tables comparing the notable differences between the 2019 park factors at various parks, courtesy the park factors listed at ESPN.com, and the park factors we have using a three-year average. Informed speculation is a key tool in a fantasy gamer’s tool belt, and being ahead of shifts in how a park plays can be difference-making for where you finish in your leagues. As a reminder, I previously dove into our park factors and pointed out ballpark renovations for 2020 at Marlins Park and Oracle Park here.

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Run-amplifying Parks in 2019 Compared to 3-year Average

*The ranks in parentheses in the 3-year average column are out of 29 parks due to our exclusion of Globe Life Park in Arlington which will no longer be home to the Rangers this year.

Three parks in this table were top-10 run-scoring venues in 2019, and only one of them rank in the top 15 in park factor for runs using our three-year average. Marlins Park has the starkest difference in run-scoring in 2019 relative to its three-year average, and with the fences being moved in for the 2020 season (which I linked to in the previous Park Factors piece from the intro), it could actually be a sneaky place for offense this year. Minute Maid Park in Houston also had a huge jump in park factor for runs, and three parks — Rogers Centre Angel Stadium, and PNC Park — moved from run-suppressing venues to run-amplifying parks last year.

Run-suppressing Parks in 2019 Compared to 3-year Average

*Chase Field started using the humidor for storing baseballs in the 2018 season, and our park factors only use post-humidor statistics for the park factor. Thus, it’s only a 2-year average as opposed to a 3-year average.

All six parks in this table ranked within the top 15 in park factor for run-scoring using the three-year average, but not a single one was a top-15 scoring park in 2019. Yankee Stadium suppressed runs by only 1.5% using a three-year average, but it cut run-scoring by a whopping 18.4% last year. If these park factors stick, these parks would swing from being dicey venues for hurlers to toe the rubber in to places to stream or use starters in daily fantasy games in.

Homer-amplifying Parks in 2019 Compared to 3-year Average

 
Holy smokes! Rogers Centre bumped homers by 31.7% in 2019 compared to 11.7% during the three-year average. Nationals Park and Guaranteed Rate Field were a couple of other launching pads that boosted taters by greater than 23% compared to a neutral field in 2019. Also, here’s Marlins Park again — and that’s prior to the aforementioned moving in of the fences for this season.

Homer-suppressing Parks in 2019 Compared to 3-year Average

 
Our top park for homers using a three-year average, Citizens Bank Park, toppled to merely seventh in 2019. It’s still a great place to chase taters, but maybe not as great as it has been in recent years. Ditto for Great American Ball Park. Chase Field flips from inflating homers a pinch compared to neutral parks using what’s actually a 2-year average since the humidor began being used in 2018 to one that took a bite out of homers by 12.2% last season.

And there’s Yankee Stadium making a second appearance in this piece. The depression in run-scoring at Yankee Stadium last year compared to the three-year average was notable, but it pales in comparison to the 21% drop in homers when comparing the two-time frames. Yankee Stadium’s park factors will be among those I track most closely early in the season. In 2018, ESPN’s park factors for Yankee Stadium for runs and homers were 1.126 and 1.166, respectively. It will be interesting to see how Yankee Stadium plays this year. For now, I’ll probably lean toward the three-year average when projecting the impact on player performances in 2020, but I’ll be ready to quickly change course during the season if it continues to play similarly to 2019.

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Josh Shepardson is a featured writer at FantasyPros. For more from Josh, check out his archive and follow him @BChad50.