The MLB is unique regarding the dimensions of each park being different. Imagine if each NFL field or NBA court were different sizes and how that would change the game. For sports bettors looking to gain an edge on the sportsbook, each venue has a Park Factor that determines whether a field is hitter or pitcher-friendly.
Park Factors take a specific MLB ballpark’s impact on in-game events and assign a number to represent its effect. While most people only consider home run numbers when determining a hitter’s ballpark, there are many more things to consider than just long balls.
What makes Park Factors so powerful is that they do not consider how skilled the players on the field are but how the park influences the game. And because the dimensions of each ballpark rarely change, these trends are consistent from year to year.
How Do Park Factors Work?
The most basic park factor stat takes the runs scored by Team A (and visiting teams) in Team A’s home ballpark and divides the result by the runs scored by Team A (and opponents) in Team A’s road games. But there are park factors that focus solely on singles, doubles, strikeouts, walks, and even foul ball pop-ups. While these factors are geared toward fantasy baseball wins, they are also helpful when looking for an edge in MLB betting online.
Different stats sites have different ways of listing park factors, but generally speaking, the baseline is a score of 100, with 100 representing a hypothetical neutral ballpark. Any value over 100 is considered a hitter-friendly park, and anything below favors pitchers.
Coors Field is consistently the ballpark with the highest PF, with a range of around 110 to 115 throughout the season. The PF at Coors is inflated because its altitude is so high and the air so thin that the ball flies further every time it comes off the bat. Meanwhile, the Seattle Mariners home stadium, T-Mobile Park, had the lowest park factors two years in a row, partly due to its humid climate.
Slugging percentages:
.557 <— Mickey Mantle, MLB career
.557 <— Willie Mays, MLB career
.557 <— MLB players at Coors Field in 1999— Codify (@CodifyBaseball) March 26, 2023
How to Use Park Factors When Betting
So how can we use this information to make better MLB bets throughout the year?
One area they can help is when reading MLB lines related to totals. Obviously, bookmakers know this and adjust lines in Colorado and Seattle, but not all sports bettors know how much stadiums impact total runs. So you may see a total much higher or lower than the average game and think you can beat it.
Instead of Over/Unders, I prefer to use these factors to find the best player props to add to my daily MLB picks.
Take Tropicana Field in Tampa Bay, for example. For reasons that are too deep to get into, Trop is consistently among ballparks with the highest strikeout rate in the MLB. So when MLB betting on pitchers at Tampa Bay, going over the strikeout total may be a winning wager under the right circumstances. Or bet on MLB props that fade hitters on the opposing team who strike out often.
I said before that I love park factors because they rarely change. However, Comerica Park and Rogers Centre made MLB news with changes in the offseason to the walls in their outfield. Keep an eye on any power hitters playing the Toronto Blue Jays in 2023, as Rogers Centre had a Park Factor for home runs of 108 in 2022 and moved in their outfield walls during the offseason.
Meanwhile, the Detroit Tigers have decided to bring in and lower the outfield fences at Comerica Park. Once referred to as “Comerica National Park” by outfielder Bobby Higginson, Comerica had the 7th lowest Park Factor in 2022 at 97. The franchise hopes the closer and lower walls will boost the excitement lacking in most Tigers games.
During the early parts of the season, I expect these changes to have a noticeable effect on runs scored that you can take advantage of while the iron is hot.
